Lavender essential oil is a well known sleep aid -- a drop or two on the pillow or bedspread at night improves sleep for many people. Some even run a diffuser slowly releasing lavender over the course of the night. But lavender doesn't work for everyone -- particularly those who aren't especially fond of its aroma. These folks might want to try Sandalwood or Chamomile; and try using these oils topically in small amounts rather than only inhaling the aroma.

These two studies show first: that Lavender has a significant statistical effect in improving sleep patterns. The second shows that not everyone is the same, and how one responds to an aroma will likely determine if that aroma will positively effect them, or not at all. Also, gender seemed to be a factor in response to an aroma.

Study: An olfactory stimulus modifies nighttime sleep in young men and women.
Goel N, Kim H, Lao RP. Department of Psychology, Wesleyan University, Middletown, Connecticut 06459, USA.

Aromatherapy is an anecdotal method for modifying sleep and mood. However, whether olfactory exposure to essential oils affects night-time objective sleep remains untested. Previous studies also demonstrate superior olfactory abilities in women. Therefore, this study investigated the effects of an olfactory stimulus on subsequent sleep and assessed gender differences in such effects. Thirty-one young healthy sleepers (16 men and 15 women, aged 18 to 30 yr, mean+/-SD, 20.5+/-2.4 yr) completed 3 consecutive overnight sessions in a sleep laboratory: one adaptation, one stimulus, and one control night (the latter 2 nights in counterbalanced order). Subjects received an intermittent presentation (first 2 min of each 10 min interval) of an olfactory (lavender essential oil) or a control (distilled water) stimulus between 23:10 and 23:40 h. Standard polysomnographic sleep and self-rated sleepiness and mood data were collected. Lavender increased the percentage of deep or slow-wave sleep (SWS) in men and women. All subjects reported higher vigor the morning after lavender exposure, corroborating the restorative SWS increase. Lavender also increased stage 2 (light) sleep, and decreased rapid-eye movement (REM) sleep and the amount of time to reach wake after first falling asleep (wake after sleep onset latency) in women, with opposite effects in men. Thus, lavender serves as a mild sedative and has practical applications as a novel, nonphotic method for promoting deep sleep in young men and women and for producing gender-dependent sleep effects.


Study: Sleep changes vary by odor perception in young adults.Goel N, Lao RP.
Department of Psychology, 207 High Street, Judd Hall, Wesleyan University, Middletown, CT 06459, USA.

Peppermint (peppermint essential oil), a stimulating odor, increases alertness while awake and therefore may inhibit sleep. This study examined peppermint's effects on polysomnographic (PSG) sleep, alertness, and mood when presented before bedtime. Twenty-one healthy sleepers (mean age +/- S.D., 20.1 +/- 2.0 years) completed three consecutive laboratory sessions (adaptation, control, and stimulus nights). Peppermint reduced fatigue and improved mood and was rated as more pleasant, intense, stimulating, and elating than water. These perceptual qualities associated with sleep measures: subjects rating peppermint as very intense had more total sleep than those rating it as moderately intense, and also showed more slow-wave sleep (SWS) in the peppermint than control session. Furthermore, subjects who found peppermint stimulating showed more NREM and less REM sleep while those rating it as sedating took longer to reach SWS. Peppermint did not affect PSG sleep, however, when these perceptual qualities were not considered. Peppermint also produced gender-differentiated responses: it increased NREM sleep in women, but not men, and alertness in men, but not women, compared with the control. Thus, psychological factors, including individual differences in odor perception play an important role in physiological sleep and self-rated mood and alertness changes.

Aflatoxin is a fungus often found in our food supply, growing on items like peanuts and corn. It is highly destructive to the liver. The essential oils studied here include Thyme and Rosemary. Though these studies may not describe much in the way of practical application directly, they do support the use of essential oils to fight fungal infections. Some oils are useful topically, and other can be ingested in small amounts for candida infections; consult a qualified natural health practitioner for more support if essential oils might benefit you in this way...

Study: Antimycotoxigenic characteristics of Rosmarinus officinalis and Trachyspermum copticum L. essential oils.

Rasooli I, Fakoor MH, Yadegarinia D, Gachkar L, Allameh A, Rezaei MB. Department of Biology, Shahed University, Iran.

Aflatoxin B1 (AFB1) is a highly toxic and carcinogenic metabolite produced by Aspergillus species on food and agricultural commodities. Natural products may regulate the cellular effects of aflatoxins and evidence suggests that aromatic organic compounds of spices can control the production of aflatoxins. With a view to controlling aflatoxin production, the essential oils from Rosmarinus officinalis (rosemary essential oil) and Trachyspermum copticum L. were obtained by hydrodistillation. Antifungal activities of the oils were studied with special reference to the inhibition of Aspergillus parasiticus growth and aflatoxin production. Minimal inhibitory (MIC) and minimal fungicidal (MFC) concentrations of the oils were determined. T. copticum L. oil showed a stronger inhibitory effect than R. officinalis on the growth of A. parasiticus. Aflatoxin production was inhibited at 450 ppm of both oils with that of R. officinalis being stronger inhibitor. The oils were analyzed by GC and GC/MS. The major components of R. officinalis and T. copticum L. oils were Piperitone (23.65%), alpha-pinene (14.94%), Limonene (14.89%), 1,8-Cineole (7.43%) and Thymol (37.2%), P-Cymene (32.3%), gamma-Terpinene (27.3%) respectively. It is concluded that the essential oils could be safely used as preservative materials on some kinds of foods to protect them from toxigenic fungal infections.

Study: Chemoprevention by thyme oils of Aspergillus parasiticus growth and aflatoxin production.

Rasooli I, Owlia P. Department of Biology, Shahed University, Iran.

The essential oils from Thymus eriocalyx and Thymus X-porlock (varieties of thyme essential oil) obtained by hydrodistillation were analyzed by GC/MS. The major components of T. eriocalyx and T. X-porlock oils were thymol (63.8, 31.7%), beta-phellandrene (13.30, 38.7%), cis-sabinene hydroxide (8.1, 9.6%), 1,8-cineole (2, 1.7%), and beta-pinene (1.31, 2%), respectively. Antifungal activities of the oils were studied with special reference to the inhibition of Aspergillus parasiticus growth and aflatoxin production. Minimal inhibitory (MIC) and minimal fungicidal (MFC) concentrations of the oils were determined. Static effects of the above oils against A. parasiticus were at 250 ppm and lethal effects of T. eriocalyx and T. X-porlock were 500 and 1000 ppm of the oils, respectively. Aflatoxin production was inhibited at 250 ppm of both oils with that of T. eriocalyx being stronger inhibitor. Transmission electron microscopy (TEM) of A. parasiticus exposed to MIC level (250 ppm) of the oils showed irreversible damage to cell wall, cell membrane, and cellular organelles. It is concluded that the essential oils could be safely used as preservative materials on some kinds of foods at low concentrations to protect them from fungal infections.

Another study has confirmed the efficacy of using essential oils in preparations such as toothpaste and mouthwash for reducing the amount of bacteria in the mouth. This is important, as it is bacteria that cause all of our dental troubles, from tooth decay, to plaque, to gum disease. You can experiment yourself by adding a drop of spearmint essential oil to your toothpaste before using; any other oil like Peppermint or Cinnamon would need SIGNIFICANT dilution (1 part to 100 for example) in your oral cleansing preparation before use.

The first study evaluates the efficacy of a toothpaste with Peppermint essential oil against a specific bacteria. The second evaluates plaque reduction compared to preparations using other active ingredients. Note that the first study mentions the potency of the lower concentrations of essential oils - as is usually the case in aromatherapy, smaller amounts of oil ususally have the greatest efficacy!

Study: Phytotherapeutic inhibition of supragingival dental plaque.

Shayegh S, Rasooli I, Taghizadeh M, Astaneh SD.Department of prosthetics, College of Dentistry, Shahed University, Tehran, Iran.

Antimicrobial activities and biofilm-formation preventive properties of Mentha piperita (peppermint essential oil) and Cuminum cyminum essential oils and chlorhexidine were assessed against Streptococcus mutans and Streptococcus pyogenes. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis led to the identification of 26 and 32 compounds in the essential oils of M. piperita and C. cyminum, respectively. Minimal bactericidal concentrations (MBC) of the oils and chlorhexidine and microbial decimal reduction time (D value) were determined. Antibacterial and in vivo biofilm preventive efficacies of all the concentrations of M. piperita oil were significantly (p<0.001)> chlorhexidine > C. cyminum order. In vivo experiments conducted on male and female volunteers who brushed with essential oil blended toothpastes indicated that lower concentrations of the oils, in particular the M. piperita oil, were significantly higher (p<0.001)>


Riep BG, Bernimoulin JP, Barnett ML.
Department of Periodontology, Humboldt University/Charité, Berlin, Germany.

The adjunctive use of antimicrobial mouthrinses to help control supragingival plaque and gingivitis has been shown to contribute significantly to patients' daily oral hygiene regimens. This controlled clinical study used an observer-blind, randomized, cross-over design in a 4-day plaque regrowth model to determine the relative efficacies of an essential oil-containing mouthrinse (Listerine Antiseptic) and an amine fluoride/stannous fluoride-containing mouthrinse (Meridol) in inhibiting the development of supragingival plaque. A 0.1% chlorhexidine mouthrinse (Chlorhexamed-Fluid) was used as a positive control, and a 5% hydroalcohol solution was used as a negative control. Dosing for each of the test mouthrinses was based on the manufacturers' label directions. Because the volume and rinse time for each of the test mouthrinses were different, each test mouthrinse had its own negative control group. On day 1 of each test period, subjects received an oral soft and hard tissue examination and a dental prophylaxis to remove all plaque, calculus, and extrinsic stain. Starting the same day, subjects refrained from all mechanical oral hygiene procedures for the next 4 days and rinsed 2x daily under supervision with their randomly-assigned mouthrinse. On day 5, each subject received a plaque assessment as well as an oral examination to assess side effects. Each test period was separated by a 2-week washout period. 23 volunteers with a median age of 26 years completed the study. Compared to the respective placebos, the median percent plaque reductions at 5 days were 23.0%, 12.2%, and 38.2% for the essential oil, amine/stannous fluoride, and chlorhexidine rinses, respectively. The plaque reductions seen in the essential oil and chlorhexidine rinse groups were statistically significant (p <> 0.05). Additionally, the essential oil rinse was significantly more effective (p <>

We've all smelled Citronella candles at some time or another, using them as mosquito repellents in the heat of summer. A pair of studies performed at The Hebrew University, Hadassah-Medical School in Jerusalem compared the efficacy of various aromatherapy candles with different essential oil or oil components as their scent. Geraniol was the most potent of the mosquito repellents; this essential oil component is most abundant in Geranium essential oil. You can easily make your own insect repellent formula, and add it to an uncented lotion base, or just use a Hazelut carrier oil as we do. Recommended oils (keep total concentration below 3% for extended use) Geranium, Citronella, Cedar, wild Lavender. You'll smell great, but the bugs won't think so...

Study: Ability of essential oil candles to repel biting insects in high and low biting pressure environments.

Müller GC, Junnila A, Kravchenko VD, Revay EE, Butler J, Orlova OB, Weiss RW, Schlein Y.
Department of Parasitology, Kuvin Centre for the Study of Infectious and Tropical Diseases, The Hebrew University, Hadassah-Medical School, Jerusalem, Israel.

The first goal of this study was to compare the degree of personal protection against biting insects provided by geraniol, linalool, and citronella candle (5%) vapors outdoors, where such products are commonly used. At a distance of 1.0 m, citronella candles reduced the number of female mosquitoes caught in Centers for Disease Control and Prevention traps by 35.4% and sand flies by 15.4%, linalool candles reduced female mosquitoes by 64.9% and sand flies by 48.5%, while geraniol candles reduced female mosquitoes by 81.5% and sand flies by 69.8%. By increasing the distance to 2 m and 3 m, the repellency dropped significantly. The second goal was to compare the degree of personal protection provided by the best performing candle, geraniol, under conditions of high and low biting pressure. The introduction of geraniol candles to protect volunteers in a high biting pressure environment reduced the mosquito pressure by an average of 56% and the sand fly pressure by 62% over a distance of 1.0 m. In the low biting pressure environment, geraniol reduced the mosquito pressure by an average of 62%. No sand flies were present at this site.

Study: Indoor protection against mosquito and sand fly bites: a comparison between citronella, linalool, and geraniol candles.

Müller GC, Junnila A, Kravchenko VD, Revay EE, Butlers J, Schlein Y.
Department of Parasitology, Kuvin Centre for the Study of Infectious and Tropical Diseases, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.

The repellent effect of 3 essential oil-based candles was evaluated in a high biting pressure environment in Israel. In human landing assays, the repellency rate of 5% citronella candles against mosquitoes was 29.0%, of 5% linalool candles was 71.1%, and of 5% geraniol candles was 85.4%. The candles with geraniol were about twice as effective as those with linalool and were about 5 times as effective as citronella candles in protecting a person from being bitten indoors by mosquitoes. The repellency rate of 5% citronella candles towards sand flies was 24.7%, of 5% linalool candles was 55.2%, and of 5% geraniol candles was 79.7%. A geraniol candle was almost 5 times as effective as a citronella candle and about twice as effective as a linalool candle in protecting a person from being bitten indoors by sand flies.

In a study recently published in 'BioMed Central Immunology', Eucalyptus essential oil (the species was not defined) was shown to stimulate immune response both in-vitro and in-vivo. The was apparently designed to drive further investigation in the subject, and does not give any details on how one might go on to utlize the information. However, Eucalyptus essential oils have long been prescribed by aromatherapists for support of lung funtion during infection. Eucalyptus has not been shown in the lab to be an especially strong anti-microbial agent; though from the results here, one may infer the reason Eucalyptus is so widely used for infectious disease - it improves phagocytic activity (the activity of white blood cells consuming foreign invaders). Further it appears to have decreased toxic effects to bone marrow after chemotherapy.

These results may support the claims made for Niaouli (a tree similar to Eucalyptus) essential oil by Dr. Kurt Schnaubelt in Advanced Aromatherapy - that this oil can dramatically support the immune system and decrease allergic response. Niaouli is prescribed to be rubbed in to the skin all over the body (some naturopaths suggest in the arm pits and on the thymus/sternum) after a warm shower when the pores are open. Blends of oils from the Myrtaceae family (Tea Tree, Ravensara, Eucalyptus, Niaouli) are likely effective together, and can be diffused regularly for immune support.

Study: Stimulatory effect of Eucalyptus essential oil on innate cell-mediated immune response.

Serafino A, Sinibaldi Vallebona P, Andreola F, Zonfrillo M, Mercuri L, Federici M, Rasi G, Garaci E, Pierimarchi P.

Besides few data concerning the antiseptic properties against a range of microbial agents and the anti-inflammatory potential both in vitro and in vivo, little is known about the influence of Eucalyptus oil (EO) extract on the monocytic/macrophagic system, one of the primary cellular effectors of the immune response against pathogen attacks. The activities of this natural extract have mainly been recognized through clinical experience, but there have been relatively little scientific studies on its biological actions. Here we investigated whether EO extract is able to affect the phagocytic ability of human monocyte derived macrophages (MDMs) in vitro and of rat peripheral blood monocytes/granulocytes in vivo in absence or in presence of immuno-suppression induced by the chemotherapeutic agent 5-fluorouracil (5-FU).

METHODS: Morphological activation of human MDMs was analysed by scanning electron microscopy. Phagocytic activity was tested: i) in vitro in EO treated and untreated MDMs, by confocal microscopy after fluorescent beads administration; ii) in vivo in monocytes/granulocytes from peripheral blood of immuno-competent or 5-FU immuno-suppressed rats, after EO oral administration, by flow cytometry using fluorescein-labelled E. coli. Cytokine release by MDMs was determined using the BD Cytometric Bead Array human Th1/Th2 cytokine kit.

RESULTS: EO is able to induce activation of MDMs, dramatically stimulating their phagocytic response. EO-stimulated internalization is coupled to low release of pro-inflammatory cytokines and requires integrity of the microtubule network, suggesting that EO may act by means of complement receptor-mediated phagocytosis. Implementation of innate cell-mediated immune response was also observed in vivo after EO administration, mainly involving the peripheral blood monocytes/granulocytes. The 5-FU/EO combined treatment inhibited the 5-FU induced myelotoxicity and raised the phagocytic activity of the granulocytic/monocytic system, significantly decreased by the chemotherapic.

CONCLUSIONS: Our data, demonstrating that Eucalyptus oil extract is able to implement the innate cell-mediated immune response, provide scientific support for an additional use of this plant extract, besides those concerning its antiseptic and anti-inflammatory properties and stimulate further investigations also using single components of this essential oil. This might drive development of a possible new family of immuno-regulatory agents, useful as adjuvant in immuno-suppressive pathologies, in infectious disease and after tumour chemotherapy.

Essential oils are commonly being tested as food preservatives...here's a couple of studies regarding their effects:

Study: The antimicrobial efficacy of plant essential oil combinations and interactions with food ingredients.

Gutierrez J, Barry-Ryan C, Bourke P.School of Food Science and Environmental Health, Dublin Institute of Technology, Cathal Brugha Street, Dublin 1, Ireland.

The objective of this study was to evaluate the efficacy of plant essential oils (essential oils) in combination and to investigate the effect of food ingredients on their efficacy. The essential oils assessed in combination included basil, lemon balm (melissa essential oil), marjoram, oregano, rosemary, sage and thyme. Combinations of essential oils were initially screened against Bacillus cereus, Escherichia coli, Listeria monocytogenes and Pseudomonas aeruginosa using the spot-on-agar test. The influence of varying concentrations of essential oil combinations on efficacy was also monitored using E. coli. These preliminary studies showed promising results for oregano in combination with basil, thyme or marjoram. The checkerboard method was then used to quantify the efficacy of oregano, marjoram or thyme in combination with the remainder of selected essential oils. Fractional inhibitory concentrations (FIC) were calculated and interpreted as synergy, addition, indifference or antagonism. All the oregano combinations showed additive efficacy against B. cereus, and oregano combined with marjoram, thyme or basil also had an additive effect against E. coli and P. aeruginosa. The mixtures of marjoram or thyme also displayed additive effects in combination with basil, rosemary or sage against L. monocytogenes. The effect of food ingredients and pH on the antimicrobial efficacy of oregano and thyme was assessed by monitoring the lag phase and the maximum specific growth rate of L. monocytogenes grown in model media. The model media included potato starch (0, 1, 5 or 10%), beef extract (1.5, 3, 6 or 12%), sunflower oil (0, 1, 5 or 10%) and TSB at pH levels of 4, 5, 6 or 7. The antimicrobial efficacy of essential oils was found to be a function of ingredient manipulation. Starch and oils concentrations of 5% and 10% had a negative impact on the essential oil efficacy. On the contrary, the essential oils were more effective at high concentrations of protein, and at pH 5, by comparison with pH 6 or 7.

This study suggests that combinations of essential oils could minimize application concentrations and consequently reduce any adverse sensory impact in food. However, their application for microbial control might be affected by food composition, therefore, careful selection of essential oils appropriate to the sensory and compositional status of the food system is required. This work shows that essential oils might be more effective against food-borne pathogens and spoilage bacteria when applied to ready to use foods containing a high protein level at acidic pH, as well as lower levels of fats or carbohydrates.

Study: Antimicrobial activity of clove and cinnamon essential oils against Listeria monocytogenes in pasteurized milk.

Cava R, Nowak E, Taboada A, Marin-Iniesta F.Grupo de Química de Carbohidratos y Biotecnología de Alimentos, Departamento de Tecnología de Alimentos, Nutrición y Bromatología, Facultad de Veterinaria, Universidad de Murcia, E-30100 Espinardo, Murcia, Spain.

The antimicrobial activity of essential oils of cinnamon bark, cinnamon leaf, and clove against Listeria monocytogenes Scott A were studied in semiskimmed milk incubated at 7 degrees C for 14 days and at 35 degrees C for 24 h. The MIC was 500 ppm for cinnamon bark essential oil and 3,000 ppm for the cinnamon leaf and clove essential oils. These effective concentrations increased to 1,000 ppm for cinnamon bark essential oil, 3,500 ppm for clove essential oil, and 4,000 ppm for cinnamon leaf essential oil when the semiskimmed milk was incubated at 35 degrees C for 24 h. Partial inhibitory concentrations and partial bactericidal concentrations were obtained for all the assayed essential oils. The MBC was 3,000 ppm for the cinnamon bark essential oil, 10,500 ppm for clove essential oil, and 11,000 ppm for cinnamon leaf essential oil. The incubation temperature did not affect the MBC of the essential oils but slightly increased the MIC at 35 degrees C. The increased activity at the lower temperature could be attributed to the increased membrane fluidity and to the membrane-perturbing action of essential oils. The influence of the fat content of milk on the antimicrobial activity of essential oils was tested in whole and skimmed milk. In milk samples with higher fat content, the antimicrobial activity of the essential oils was reduced.

These results indicate the possibility of using these three essential oils in milk beverages as natural antimicrobials, especially because milk beverages flavored with cinnamon and clove are consumed worldwide and have been increasing in popularity in recent years.

The following study notes a significant difference in response to different aromas - here, peppermint and ylang ylang aromas were tested, and the participant's level of awareness and calmness. Peppermint significantly heightened alertness and response time, where ylang ylang brought about calmness and slowed response time. And our big question: why don't studies like this get any press, where the recent one performed in the US showing no change in some saliva chemical markers was all over the media? With the headline that aromatherapy doesn't work? It's one thing to say different aromas do not affect saliva chemical composition...but this is the only reasonable conclusion the study could really come to. Delving into the research reveals all sorts of studies with results similar to the following:

Study: Modulation of cognitive performance and mood by aromas of peppermint and ylang-ylang.

Moss M, Hewitt S, Moss L, Wesnes K.Human Cognitive Neuroscience Unit, Division of Psychology, University of Northumbria, Newcastle upon Tyne, United Kingdom.

This study provides further evidence for the impact of the aromas of plant essential oils on aspects of cognition and mood in healthy participants. One hundred and forty-four volunteers were randomly assigned to conditions of ylang-ylang aroma, peppermint aroma, or no aroma control. Cognitive performance was assessed using the Cognitive Drug Research computerized assessment battery, with mood scales completed before and after cognitive testing. The analysis of the data revealed significant differences between conditions on a number of the factors underpinning the tests that constitute the battery. Peppermint was found to enhance memory whereas ylang-ylang impaired it, and lengthened processing speed. In terms of subjective mood peppermint increased alertness and ylang-ylang decreased it, but significantly increased calmness.

These results provide support for the contention that the aromas of essential oils can produce significant and idiosyncratic effects on both subjective and objective assessments of aspects of human behavior. They are discussed with reference to possible pharmacological and psychological modes of influence.