Mechanism of Action
German chamomile flowers contain 0.24%–1.9% volatile oil. The oil is made up of a variety of compounds. The principal terpenoids are α-bisabolol and chamazulene. Chamazulene has antioxidant and anti-inflammatory activity.1,2 Chamomile flowers also contain the bioflavonoids apigenin, quercetin, and patuletin, which are flavonoids.3
Apigenin has demonstrated anxiolytic properties in laboratory studies and seems to be an important constituent contributing to chamomile’s effectiveness as a sleep aid.4 Apigenin binds to benzodiazepine receptors in the brain and results in CNS-depressant effects.5 Quercetin is an anti-inflammatory, slows the release of histamine, and has anticancer properties.6
The soporific action of a chamomile extract was investigated in a sleep-disturbed rat model. At a dose of 300 mg/kg chamomile, a significant reduction in sleep latency time was noted. However, the chamomile did not have a significant effect regarding total wakefulness time, non-rapid eye movement (non-REM) sleep, delta activity during non-REM sleep, and REM sleep. At a dose of 3 mg/kg, the benzodiazepine receptor antagonist flumazenil significantly decreases the sleep latency effect of chamomile extract. The authors concluded that chamomile extract has benzodiazepine-like, sleep latency–reducing activity in rats.7
Clinical trials in humans are limited and results are mixed.
A randomized controlled trial was conducted to test the soporific qualities of chamomile. Eighty Taiwanese women, all recently postnatal and reporting poor sleep quality, were the subjects. They were randomly assigned to either an experimental group or a control group. The 40 women in the experimental group drank one cup of chamomile tea (made with 2 g of dried flowers) daily for 2 weeks. The women in the control group did not have chamomile, just standard post-pregnancy care. The effect of the chamomile plus normal postpartum care versus just normal postpartum care was assessed using the Edinburgh Postnatal Depression Scale and the Postpartum Fatigue Scale. At one cup per day the chamomile group had significantly less insomnia and depression. However, the positive effects for sleep and depression had almost completely faded 4 weeks after conclusion of the trial, which suggests that the effects of chamomile only lasted while the subjects ingested it. In conclusion, chamomile tea seems to alleviate depression and insomnia in postpartum women while being ingested.8
In a study done on patients with chronic insomnia, chamomile was tested for efficacy and safety in regard to treating subjective sleep and daytime symptoms. The study was placebo controlled, randomized, and double blind. The 34 patients ranged in age from 18 to 65 years. All patients were suffering from Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) primary insomnia for at least 6 months leading up to the study. Patients were randomly given 270 mg of chamomile BID or placebo for 28 days. The results were measured with sleep diaries. Daytime functions were also measured as a secondary outcome. In the end, only daytime functioning was positively affected, and not by much, as the researchers did not deem it statistically significant. The chamomile and placebo groups had sleep diary scores that were not significantly different, including sleep latency, sleep efficiency, wake after sleep onset, total sleep time, sleep quality, and number of awakenings. Adverse event outcomes did not differ between the chamomile and placebo groups.9
The Department of Family Medicine and Community Health outpatient clinic at The University of Pennsylvania recruited 61 patients with general anxiety disorder (GAD) and assessed chamomile for safety and efficacy. The study was randomized, double blind, and placebo controlled for 8 weeks. All patients met the criteria for mild-to-moderate GAD from the DSM-IV. There were 28 in the chamomile extract group and 29 in the placebo group.
Several standard tests were used to rate symptoms, including the Psychological General Well-Being index, Beck Anxiety Inventory, Clinical Global Impressions Severity, and the Hamilton Anxiety Rating (HAM-A). Side effects were also assessed. Researchers obtained outcome measurements immediately before the study and then at the end of weeks 2, 4, 6, and 8 of the trial. Subjects were given one capsule daily of chamomile (standardized to 1.2% apigenin) or placebo during the first week of the study. The dose was increased to two capsules for the second week. After the second week, if the subject’s symptoms were not at least 50% improved compared to baseline by using the HAM-A Scoring system, doses were increased to three capsules per day. This test was repeated in week 4, and doses were increased to four capsules per day if symptoms failed to improve by at least 50%. The same test was repeated in week 5, and the dose was increased to five capsules per day if 50% improvement was not seen. The maximum dose did not exceed five capsules per day, continuing through to the eighth week, and 1100 mg was the maximum daily dose for any patient. Results of the study were promising, with HAM-A Scores improved significantly in the chamomile group compared with the placebo group. The chamomile extract showed both efficacy and tolerability in subjects with mild-to-moderate GAD.10
Safety in Pregnancy and Breastfeeding
There is limited information regarding pregnancy and breastfeeding in the scientific and traditional literature. Serious adverse effects on fetuses or breastfed children have not been reported.11
Chamomile has generally regarded as safe status in the United States, primarily because of its long history of diverse traditional use.2 However, rare allergic reactions have been documented. Chamomile is not wind pollinated and therefore not associated with allergic rhinitis. However, rare cases of cross-reactivity between chamomile pollen and wind-borne pollens of other plants in the Asteraceae have been documented or may be caused by adulteration by “dog chamomile” (Anthemis cotula).2,12
For anxiety and insomnia, chamomile is often combined with other herbs in a formula. Typical doses range from one to two capsules (to 1000 mg per cap) QD to QID.
German chamomile has an extensive history of medicinal use. Several ancient cultures have documented its use, including Roman, Greek, Egyptian, and other civilizations. The Egyptians used chamomile for treating anxiety and to treat fevers associated with malaria. Ancient Greek physicians prescribed chamomile for nervous stomach, headaches, and colic.
Chamomile is included in the pharmacopoeias of at least 26 countries, including the United Kingdom, Belgium, and Germany. It is one of the most popular herbal remedies worldwide, being used to treat nervous indigestion, upset stomach, gastric ulcers, and colic. It is also widely used to promote relaxation and sleep. Topically, it is used to treat a variety of acute and chronic inflammatory skin disorders.
1 Nat Prod Res. 2014;28(24):2321–3. doi: 10.1080/14786419.2014.931393. Epub 2014 Jul 1. Antioxidant and radical scavenging activities of chamazulene. Capuzzo A, Occhipinti A, Maffei ME.
2 Fitoterapia. 2015;106:122–8. doi: 10.1016/j.fitote.2015.08.010. Epub 2015 Aug 21. Revisited anti-inflammatory activity of matricine in vitro: Comparison with chamazulene. Flemming M, Kraus B, Rascle A, Jürgenliemk G, Fuchs S, Fürst R, Heilmann J.
4 Evidence-Based Complementary and Alternative Medicine Volume 2015, Article ID 105256, page 2. Updates on Nutraceutical Sleep Therapeutics and Investigational Research. Michael Yurcheshen, Martin Seehuus, and Wilfred Pigeon.
5 Phytotherapy Res. 1996;10:177–9. Benzodiazepine compounds and GABA in flower heads of matricaria chamomilla. Avallone R, Zanoli P, Corsi L, Cannazza G, Baraldi M.
6 Nutrients. 2016.8,529;doi:103390/nu8090529. Molecular targets underling the anticancer effects of quercetin: an update. Kahn F, Niaz K, Maqbool F, Hassan FI, Abdollahi M, Venkata KCN, Nabavi SM, Bishayee A.
7 Biol Pharm Bull. 2005;28(5):808–10. Hypnotic activities of chamomile and passiflora extracts in sleep-disturbed rats. Shinomiya K, Inoue T, Utsu Y, Tokunaga S, Masuoka T, Ohmori A, Kamei C.
8 J Adv Nurs. 2016;72(2):306–15. doi: 10.1111/jan.12836. Epub 2015 Oct 20. Effects of an intervention with drinking chamomile tea on sleep quality and depression in sleep disturbed postnatal women: a randomized controlled trial. Chang SM, Chen CH.
9 BMC Complement Altern Med. 2011;11:78. doi: 10.1186/1472-6882-11-78. Preliminary examination of the efficacy and safety of a standardized chamomile extract for chronic primary insomnia: a randomized placebo-controlled pilot study. Zick SM, Wright BD, Sen A, Arnedt JT.
10 J Clin Psychopharmacol. 2009;29(4):378–82. A randomized, double-blind, placebo-controlled trial of oral Matricaria recutita (chamomile) extract therapy of generalized anxiety disorder. Amsterdam J, LI Y, Soeller I, et al.
12 J Allergy Clin Immunol 1989:84:35.3–8. Anaphylactic reaction after the Ingestion of chamomile tea: a study
of cross-reactivity with other composite pollens. Subiza J, Subiza JL, Hinojosa M, Garcia R, Jerez M, Valdivieso R, Subiza E.