Teratogenic potential of quercetin in the rat.

A single oral dose of 2, 20, 200, or 2000 mg quercetin/kg was administered to pregnant rats on the morning of day 9 of gestation. Other groups of pregnant rats received similar oral doses of quercetin daily, on days 6-15 of gestation. Some quercetin-treated groups showed a significant decrease in the average weight of day-20 foetuses compared with the corresponding control weight. However, studies of the foetuses recovered on day 20 of gestation failed to reveal any reproducible dose-related syndrome of teratogenic effects attributable to quercetin treatment.