Citronella Oil
Scientific Name(s): Andropogon nardus L., Cymbopogon nardus L. Rendle, Cymbopogon winterianus Jowitt
Common Name(s): Ceylon oil, Citronella, Citronella oil
Medically reviewed by Drugs.com. Last updated on Oct 20, 2023.
Clinical Overview
Use
Citronella oil is used in small amounts to flavor foods, scent cosmetics, and repel insects. It has been used in aromatic tea as a vermifuge, diuretic, and antispasmodic, although no clinical trials have been performed.
Dosing
There are no published clinical studies of citronella that establish appropriate dosage. In a systematic review, concentrations of 20% and 25% citronella were reported to provide equivalent mean protection time (480 minutes) as the same concentrations of DEET against bites from Anopheles and Culex spp of mosquitoes but not Aedes spp. Protection may be improved with the addition of 5% vanillin.
Contraindications
Contraindications have not yet been identified.
Pregnancy/Lactation
Information regarding safety and efficacy in pregnancy and lactation is lacking. Avoid use.
Interactions
None well documented.
Adverse Reactions
Citronella oil may cause contact dermatitis.
Toxicology
Ingestion may be fatal in some cases.
Scientific Family
- Poaceae (grasses)
Botany
C. nardus (Ceylon citronella) and C. winterianus (Java citronella) are both perennial grasses.USDA 2016 These 2 species are distinguished from each other by different leaf morphologies and chemical composition.Wijesekera 1973 This plant should not be confused with the citrosa plant, Pelargonium citrosa, introduced into North America as a biological repellent against mosquitoes.Matsuda 1996 Citronella's essential oils are obtained by steam distillation of the fresh or dried grass. The Java-type oil generally is considered to be of superior quality to the Ceylon oil.Khan 2009
History
Citronella oil has been used as a flavoring for foods and beverages in very low quantities (approximately 45 ppm).Khan 2009 In traditional medicine, the oil has been used as an aromatic tea, vermifuge, diuretic, and antispasmodic.Khan 2009 Perhaps the most widely recognized use for the oil is as an insect repellent. It is sometimes incorporated into perfumes and soaps.Evans 1989
Chemistry
Citronella oil contains a number of fragrant fractions of which citronellal, geraniol, and citronellol are the major components.Khan 2009, Windholz 1983 Gas chromatographic analysis of the Ceylon variety indicates that the oil contains large amounts of monoterpenes (approximately 27%), as opposed to the Java variety, which contains only 1% to 3%, mostly in the form of limonene.Wijesekera 1973 Both types contain comparable amounts of geraniol (18% to 21%). The Java oil is superior to the Ceylon type; the Java variety contains 16% citronellol and 33% citronellal, whereas the Ceylon type contains only 8% and 5%, respectively.Wijesekera 1973 The chemical composition of essential oil can vary tremendously. Other predominant compounds in citronella oil include citronellyl acetate, beta-bourbonene, geranyl acetate, elemol, L-borneol, and nerol.Akhila 1986, Patra 1997, Wijesekera 1973 A geraniol-rich mutant of citronella has been developed; it is reported to have a geraniol content as high as 60%.Ranaweera 1996 The wild Ceylon variety (commonly called mana grass) has a chemical profile very different from the 2 cultivated types.Wijesekera 1973
Uses and Pharmacology
Insect repellant
Fractional distillation of Ceylon citronella yielded 13 fractions that were tested against mosquito larvae. Monoterpene fractions containing mycrene were very lethal to late third instar Culex quinquefasciatus larvae.Pattnaik 1996 Elemol and methyl iso-eugenol were responsible for larvicidal activity in other fractions.Pattnaik 1996
A systematic review and meta-analysis was conducted on 11 controlled laboratory experimental studies in humans that investigated the effectiveness of citronella preparations in preventing bites from Aedes, Anopheles, and Culex mosquitoes, which transmit dengue fever, malaria, and encephalitis, respectively. The difference in mean protection time against bites and percentage of repellency compared to control were the measured outcomes. Studies were included if either the cage or room method was used. At least 4 different definitions of "protection time" were used among the studies in the systematic review. Citronella products varied in dosage form (ie, cream, lotion, solution, spray, wristband), preparation method, citronella oil concentration (1.25% to 30%), and amount of citronella oil used. Most of the cage-method studies used DEET 4% to 25% as a comparator, while the room-method studies compared citronella to DEET 19% to 50%. Overall, citronella 10% to 30% with or without the addition of 5% vanillin provided a shorter mean protection time (19.7 to 390 minutes) against Aedes spp bites compared to DEET 4% to 25% (234.4 to 480 minutes). In contrast, citronella 20% and 25% provided the same mean protection time (480 minutes) as DEET at the same concentration against Anopheles and Culex spp. Additionally, 10% citronella had a longer mean protection time (312 minutes) against Culex spp than 7% DEET (288 minutes) but not 15% DEET (420 minutes). The addition of 5% vanillin to 25% citronella protected subjects longer (480 minutes) than 25% DEET (360 minutes) against bites from Anopheles mosquitoes. In 2 studies investigating efficacy against Anopheles mosquitoes, citronella at concentrations of 5%, 40%, and 25% plus vanillin 5% provided 100% repellency for at least 3 hours; however, the 25% plus 5% vanillin and 40% citronella oil alone provided continued complete protection for up to 6 hours. By the 6th hour, the repellency of the 5% citronella product dropped to 77.5%.Kongkaew 2011
Mosquito repellency, irritation level, and smell satisfaction of 100% citronella oil were measured during both indoor (N=101) and outdoor (N=140) conditions in a controlled study in Nepal where Culex and Aedes mosquitoes are prevalent. After application of 100% citronella oil, 2-hour repellency was found to be significantly better in the citronella group (3.9% bitten) compared to controls who received no citronella oil (71.1% bitten; P<0.001). Similarly, the mean number of mosquito bites after 2 hours was also significantly lower in the citronella than the control group (0.07 vs 2.4, respectively; P<0.001). Although no appreciable differences were observed for citronella repellency effects between indoor and outdoor groups (32.7% and 37.9% bitten, respectively), a statistically significant difference was observed between indoor and outdoor groups in the mean number of bites (0.9 and 1.3, respectively; P=0.02). Smell satisfaction was reported as 67.7% "good" and 16.5% "very good" with 7 times more "very good" responses occurring within the outdoor group. Additionally, the oil was well tolerated in both indoor and outdoor settings with no irritation reported by more than 85% of participants and only slight irritation noted by the rest.Sajo 2015
Other uses
Citronella oil has been found to have in vitro antibacterial activity against gram-positive organisms.Khan 2009 The essential oil also displays antifungal activity.Temple 1991
Dosing
There are no recent published clinical studies of citronella which establish appropriate dosage.
Pregnancy / Lactation
Information regarding safety and efficacy in pregnancy and lactation is lacking. Avoid use.
Interactions
None well documented.
Adverse Reactions
Citronella oil has been reported to cause contact dermatitis in humans.Khan 2009
Toxicology
Animal toxicity studies have shown that citronella oil has an LD50 in mice of 4,600 mg/kg and in rats of 7,200 mg/kg. A dose of 1 to 4 mL/kg given by stomach tube in rabbits caused paralysis, coma, and death. At least 1 case of death has been reported in a child who ingested an unknown quantity of citronella oil. A review of 5 cases of childhood citronella oil poisoning suggests that dilution of the oil following ingestion may be sufficient to treat most cases of ingestion and that emesis may be induced with a relatively low risk of major pulmonary complications. If spontaneous vomiting has occurred, observation for respiratory symptoms is required.Temple 1991
References
Disclaimer
This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this product. This information does not endorse this product as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this product. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this product. This information is not specific medical advice and does not replace information you receive from your health care provider. You should talk with your health care provider for complete information about the risks and benefits of using this product.
This product may adversely interact with certain health and medical conditions, other prescription and over-the-counter drugs, foods, or other dietary supplements. This product may be unsafe when used before surgery or other medical procedures. It is important to fully inform your doctor about the herbal, vitamins, mineral or any other supplements you are taking before any kind of surgery or medical procedure. With the exception of certain products that are generally recognized as safe in normal quantities, including use of folic acid and prenatal vitamins during pregnancy, this product has not been sufficiently studied to determine whether it is safe to use during pregnancy or nursing or by persons younger than 2 years of age.
Further information
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