The patient had been implanted with a mechanical valve and was taking an anti-coagulant medication called warfarin, designed to thin the blood and reduce the chances of stroke. "Warfarin is an effective and reliable anti-coagulant and as a result is used commonly," says Dr. Louise Pilote an internist and epidemiologist at the MUHC and Associate Professor of Medicine at McGill University. "We are aware of several herbal products that should not be taken with warfarin, such as garlic, onion and ginger, but this is the first time we have documented a life-threatening reaction when combined with chamomile."
Warfarin is derived from coumarin, a chemical compound with anti-coagulant properties found in many plants, including chamomile. "It seems the chamomile acted synergistically with the warfarin in this case," says Dr. Pilote. "Although this is a rare case, it highlights the potential dangers of mixing herbal remedies with physician prescribed medications."
Camomile tea is taken to treat a range of ailments including toothache, sore thoats, digestive problems and insomnia--it is known as the night-time tea because it acts as a mild sedative. Camomile lotion is often used to treat skin conditions psoriasis, eczema and acne as well as helping soothe insect bites.
The McGill University Health Centre (MUHC) is a comprehensive academic health institution with an international reputation for excellence in clinical programs, research and teaching. The MUHC is a merger of five teaching hospitals affiliated with the Faculty of Medicine at McGill University––the Montreal Children's, Montreal General, Royal Victoria, and Montreal Neurological Hospitals, as well as the Montreal Chest Institute. Building on the tradition of medical leadership of the founding hospitals, the goal of the MUHC is to provide patient care based on the most advanced knowledge in the health care field, and to contribute to the development of new knowledge.
Canadian Medical Association Journal