Book excerpt: Poisoning due to Cucurbitaceous vegetables seems to be linked to intake of immensely bitter vegetables. The bitter and toxic compounds in these vegetables are cucurbitacins, which are well known in wild varieties of these food plants and their related species. The cultivated forms, on the other hand, have during cultivation been selected for being free of the bitter and toxic compounds. Occasionally, cultivars of cucurbitaceous food plants (e.g. squash) back-mutate and regain the ability to produce toxic amounts of cucurbitacins. This review summarises the information available on cucurbitacins in food plants of the family Cucurbitaceae, with the aim to lay down background information required to evaluate the potential risk of being intoxicated by cucurbitacins as a part of the safety assessment of cucurbitaceous food plants, and especially in relation to genetically modified Cucurbitaceous plants.