[Ginkgo biloba--effect, adverse events and drug interaction].

Ginkgo is probably one of the most widely used medicinal herbs in Europe. In Norway products of ginkgo leaf extract have been approved by the Norwegian Medicines Agency for the following indication: traditionally used to improve blood circulation, for example, cold hands and feet. Elsewhere, ginkgo is used for cognitive impairment and dementia, acute ischaemic stroke, intermittent claudication, tinnitus and age-related macular degeneration. Evidence of the efficacy of ginkgo for these indications has previously been studied by the Cochrane Collaboration. In this update we have repeated all the searches in Medline and EMBASE exactly as described in the five Cochrane Systematic Reviews (last search date: 16.02.2011). We identified two new randomised and placebo-controlled studies on cognitive impairment and dementia (3187 patients) and one study on acute ischaemic stroke (3069 patients). The results of these studies gave no reason to change the conclusions of earlier reviews by the Cochrane Collaboration. There is no convincing evidence that ginkgo is effective for cognitive impairment or dementia, acute ischaemic stroke, intermittent claudication or tinnitus. There is still a lack of conclusive evidence for the effect on age-related macular degeneration. Ginkgo leaf extract appears to be safe to use, with no excess side effects compared with placebo. It can cause some minor side effects such as stomach upset, headache, dizziness, constipation, forceful heartbeat, and allergic skin reactions. There is some concern that ginkgo leaf extract might increase the risk of bruising and bleeding, and interactions with anticoagulants/antiplatelet drugs cannot be ruled out. As a general precaution, it is recommended withdrawing ginkgo two weeks before elective surgery.