Benefits
Anxiety rating scores in placebo-controlled extract trials
In an 8 week double blind trial of 57 adults diagnosed with generalized anxiety disorder, chamomile extract lowered Hamilton Anxiety Rating Scale scores more than placebo (P = 0.047). In a longer trial of people who had already responded, staying on chamomile did not significantly reduce relapse (P = 0.16), though symptom scores rose less than on placebo. Neither trial tested everyday stress in healthy people.
Traditional use as a bedtime tea
Chamomile tea is a traditional evening drink, and apigenin, one of its flavonoids, binds central benzodiazepine receptors in laboratory work and reduced anxiety-like behavior in mice. Tradition and animal work are not human trials and do not show that chamomile works like a sleep medication. The controlled human results are summarized in the sleep quality benefit on this page.
Traditional use for digestive comfort
Chamomile has long been used to settle the stomach, and animal studies summarized in a review report antispasmodic and anti-inflammatory effects. None of the studies cited on this page tested digestion in people, so this rests on tradition and animal work only, and chamomile is not a treatment for digestive diseases.
Anti-inflammatory activity in animal studies
The flowers contain flavonoids and an essential oil rich in alpha bisabolol and chamazulene, and animal model studies summarized in a review report anti-inflammatory activity. No human trial cited on this page measured inflammatory markers, and studies of chamomile applied to the skin say nothing about drinking it or taking it in a capsule.
HbA1c and insulin readings in an 8 week tea trial
In a single blind trial, 64 adults aged 30 to 60 with type 2 diabetes drank chamomile tea (3 g in 150 mL) three times a day after meals or followed a water regimen for 8 weeks. HbA1c (p = 0.03), insulin and insulin resistance fell more with tea, as did total cholesterol and triglycerides. The control was plain water rather than a placebo drink, and the trial does not show effects in people without diabetes.
Self-rated sleep quality on questionnaires
In a single blind trial, 60 adults aged 60 and over took 200 mg chamomile extract or flour capsules twice daily for 28 days, and self-rated sleep quality (PSQI) ended better with chamomile. A pooled analysis of five trials found a PSQI drop of about 1.9 points with very high heterogeneity and no gain in sleep duration or efficiency. A placebo-controlled trial in chronic insomnia found no sleep diary difference.
Mechanism of action
Apigenin binding at central benzodiazepine receptors
Apigenin, a flavonoid isolated from chamomile flowers, competed with a benzodiazepine for binding to central benzodiazepine receptors in laboratory tests and reduced anxiety-like behavior in mice, with mild sedation only at a tenfold higher dose. How much apigenin from tea or a capsule reaches the human brain is not established, and this work does not show that chamomile acts like a prescription sedative.
Anti-inflammatory and antispasmodic activity in animal studies
A review of chamomile research reports anti-inflammatory and antispasmodic effects in animal models and antiplatelet activity in test tube work, from flowers rich in apigenin, alpha bisabolol and chamazulene. These findings come from cell and animal models and have not been shown to produce measured effects on inflammation or digestion in the human research cited on this page.
Clinical trials
Two-phase relapse prevention trial in adults with moderate to severe generalized anxiety disorder (NCT01072344), funded by NIH. All 179 took open-label chamomile extract 1,500 mg a day (500 mg three times daily) for 12 weeks; the 93 responders were then randomized to continue chamomile (46) or switch to placebo (47) for 26 weeks. Primary outcome: time to relapse. (Mao et al. 2016, Phytomedicine)
179 adult outpatients entered the open-label phase; only the 93 who responded went on to the randomized phase.
The primary outcome was not met: relapse occurred in 7 of 46 on chamomile versus 12 of 47 on placebo (hazard ratio 0.52, 95% CI 0.20 to 1.33, P = 0.16). Secondary results favored chamomile: GAD-7 scores rose less than on placebo (P = 0.0032), and body weight and mean arterial blood pressure fell more. HAM-A and Beck inventory scores showed the same trend without reaching significance. Possibly or probably related adverse events were similar (17.4% versus 19.1%) and all were mild.
Single blind randomized trial in adults aged 30 to 60 with type 2 diabetes: chamomile tea (3 g in 150 mL hot water) three times a day immediately after meals versus a water regimen for 8 weeks. (Rafraf et al. 2015, J Endocrinol Invest)
64 adults aged 30 to 60 with type 2 diabetes (32 per group).
Compared with water, chamomile tea lowered HbA1c (p = 0.03), serum insulin and HOMA-IR insulin resistance (both p < 0.001), total cholesterol (p = 0.001), triglycerides (p < 0.001) and LDL cholesterol (p = 0.05); HDL cholesterol did not change in either group. The control was plain water rather than a placebo drink, and the trial does not show effects in people without diabetes.
Randomized, double blind, placebo-controlled trial of German chamomile extract standardized to 1.2% apigenin, 220 mg capsules started at 1 a day and raised to as many as 5 a day, for 8 weeks in outpatients with generalized anxiety disorder; NIH funded. (Amsterdam et al. 2009, J Clin Psychopharmacol)
57 randomized adult outpatients with mild to moderate anxiety (28 chamomile, 29 placebo).
Total HAM-A anxiety scores fell more on chamomile than on placebo (P = 0.047). Secondary outcomes moved in the same direction, but the trial was not powered to detect them. One patient in each group stopped because of adverse events, and adverse event counts did not differ (P = 0.417).
Single blind randomized trial: chamomile extract 200 mg capsules twice daily versus 200 mg wheat flour capsules for 28 days in a day care nursing home in Karaj, Iran; outcome was the Pittsburgh Sleep Quality Index. (Adib-Hajbaghery et al. 2017, Complement Ther Med)
60 adults aged 60 and over (mean age about 70) with low baseline sleep quality.
Baseline sleep quality was low in both groups and did not differ (P = 0.639), although one component, habitual sleep efficiency, differed at baseline. After 28 days, PSQI sleep quality was significantly better with chamomile than with flour capsules (P < 0.05). Sleep was self-rated and the trial was single blind.
Randomized, double blind, placebo-controlled pilot in adults with DSM-IV chronic primary insomnia for at least 6 months: 270 mg chamomile extract twice daily for 28 days; primary outcomes were sleep diary measures. Funded by a University of Michigan seed grant and an NIH clinical research award; the extract maker gave no financial support. (Zick et al. 2011, BMC Complement Altern Med)
34 adults aged 18 to 65.
None of the diary measures (total time, efficiency, latency, wake time after onset, quality and number of awakenings) differed significantly from placebo. Effect sizes for latency, night awakenings and fatigue were moderate in favor of chamomile and total time was moderate in favor of placebo, none significant. Daytime functioning showed a nonsignificant advantage, and adverse events did not differ.