An Unexpected Anticholinergic Effect due to Yarrow (Achillea millefolium)

Abstract

Yarrow (Achillea millefolium) is a widely used plant in folk medicine due to its anti-inflammatory, anti-ulcer and estrogen-related effects. Some side effects including dermal allergic reactions have been reported owing to this herbal remedy. However, the literature about Achillea species do not include any side effects indicating anticholinergic toxicity. A 43-year-old female patient presented to the emergency department with blurred vision, dryness in the mouth, facial flushing and palpitation. She did not have any systemic illnesses and she denied taking any other herbal drugs or medications except yarrow tea (five cups a day, for one week), which she used for the treatment of menometrorrhagia. The constituents of the Achillea species identified in the former studies are highly bioactive, but their effects are not entirely known. Although the Achillea species have been considered as safe medicinal plants, the various pharmacological effects of Achillea species should be cautiously handled