Gastrointestinal bleeding secondary to interaction of Artemisia absinthium with warfarin.

Artemisia absinthium, also known as wormwood, is used widely as an herbal medicine. In this report, we introduce an 82-year-old Turkish woman who was treated with warfarin for atrial fibrillation and was hospitalized for gastrointestinal bleeding as a result of extremely elevated international normalized ratio (INR) after consumption of A. absinthium. Naranjo adverse drug reaction probability scale score was 6, which indicated a probable relationship between the patient's elevated INR and her concomitant use of wormwood and warfarin. Clinicians should be vigilant about potential dangers of herbal medicines taken with conventional drugs, and patients taking drugs with a narrow therapeutic index, such as warfarin, should be educated about avoiding consumption of herbal medicines.