The presence of ecdysone molecules in the plant kingdom is nearly universal. Plants use ecdysteroids as natural insecticides, yet ecdysteroids are completely innocuous in mammals. Despite their steroidal skeleton, they have no teratogenic, sex-hormonal, anabolic, or analgesic properties. Moreover, humans consume large amounts of dietary ecdysteroids without such effects. For example, fresh spinach contains over 100 µg/g of 20-hydroxyecdysone. In rats, daily administration of 2 g/kg of ecdysteroid for 35 days has no effect on serum chemistry or organ weight. Ingested ecdysteroids survive the acidic conditions of the stomach, are quickly taken up, are promptly removed from the bloodstream, and are disposed of primarily through biliary excretion into the intestine. "