A courgette plant, Cucurbita pepo. The picture shows a garden plant with three potential courgettes visible. The oldest is above centre; the adhering flower more withered than on the younger fruit below it. To the bottom is a third, immature, female flower (edge, to right). Courgettes belong to the family Cucurbitaceae, that includes cucumbers, pumpkins and melons. Members of the family may produce a triterpene chemical, cucurbitacin. This bitter tasting substance is thought to have evolved to deter grazing animals. It is cytotoxic, and of interest as an anti-cancer agent. Its ingestion may cause toxic courgette syndrome in humans, including cramps, diarrhoea and hair loss. The compound is rarely present in plants grown from commercial seed. It may occur if gardeners save their own seed, due to cross-pollination with wild plants of the family, such as White Bryony, Bryonia dioica.