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| Symptoms of anaphylaxis due to chamomile. Image: http://www.nlm.nih.gov/ |
Chamomile is generally well tolerated among users, however, severe allergic reactions can occur in individuals that have allergies to other related plants in the Asteraceae family (Thorne Research Inc. 2008). Such individuals are strongly cautioned to avoid chamomile in order to prevent hypersensitivity reactions (Natural Standard Monograph, 2010). Despite its widespread tolerability, several studies have shown that the inhalation of chamomile pollen can induce anaphylactic reactions in people suffering from asthma (Reider 2000; De la Torre, 2001).
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| Contact dermatitis caused by topical chamomile treatment. Image: www.revolutionhealth.com |
Very few reports have been published that document interactions between chamomile and other herbs or pharmaceutical drugs. Thus, due to the lack of sufficient empirical evidence, theoretical postulations have only been able to suggest potential drug interactions with chamomile (McKay D, Blumberg J, 2006).
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| Coumarin under the microscope. Image: www.microscopy.fsu.edu |
It has been suggested that coumarin, a blood-thinning compound found in German chamomile, should theoretically increase the effects of warfarin by preventing blood coagulation (Miller, 1998; Segal, 2006). It has also been postulated that chamomile may enhance the blood thinning effects of drugs such as acetaminophen when treatments are taken together (Abebe, 2002). Lastly, it has been suggested that chamomile may increase the effects of sedative drugs such as alcohol and opioid analgesics, thus, consuming chamomile with sedative drugs is highly cautioned (O’Hara et al., 1998).
