No significant safety concerns associated with Ginkgo biloba leaf extract have been clearly identified in human clinical trials. Although case studies have indicated that ginkgo might increase bleeding risk,[1] a meta-analysis of 18 randomized controlled trials found no higher risk of bleeding in participants who took standardized extracts.[2] There have been rare reports of seizures among people with epilepsy who supplemented with ginkgo, perhaps due to stimulation of the enzymatic breakdown of anticonvulsant medication.[1] Finally, experiments in rodents have suggested that ginkgo extract may be carcinogenic.[3]