Ginkgo biloba is one of the oldest living tree species. It is cultivated around the world for its medicinal properties and aesthetic value. The seeds and the leaves have been used in traditional medicine to treat respiratory diseases, circulatory disorders, sexual dysfunction, and loss of hearing. Ginkgo biloba extract exhibits anti-infective (1), chemopreventive (2), anticancer (3), and cytotoxic (4) effects in vitro.
Supplementation with Ginkgo improved cognitive performance in healthy adults (5), and demented patients (6) but data are conflicting (7) (8) (9) (10) (11). However, findings from the Gingko Evaluation of Memory (GEM) study, the largest trial of Ginkgo for dementia so far, indicate that Ginkgo is ineffective in decreasing the incidence of dementia or Alzheimer's disease in elderly individuals (30); another randomized trial reported similar findings (43). Further, gingko did not slow down cognitive decline in older adults with normal cognition or with mild cognitive impairment (32).
It was less effective than the standard treatment for ADHD in children (37).
Ginkgo biloba may also reduce the severity of acute mountain sickness, but the evidence is mixed (25) (26) (27) (28). More studies are warranted.
Ginkgo has also been implicated in reducing the risk of ovarian cancer but this is based only on epidemiological and biological data (12). Orally administered capsules of Ginkgo biloba exocarp polysaccharides reduced tumor area in patients with gastric cancer (4). In another study, an injectable form of Ginkgo extract and 5-flurouracil were administered to patients with advanced colorectal cancer. Data suggests benefits of the combination therapy (13). But data from the GEM study, in which cancer was the secondary outcome, do not support Gingko's effectiveness in reducing cancer risk (38).
High doses of a Ginkgo biloba extract showed carcinogenic effects in mice (44). However, dietary supplements in use today have much smaller concentrations.
Human data regarding ginkgo's effects on cancer are inconclusive (4) (12) (38).