Bitter gourds have long been prized in Asia for a trait that’s considered a defect in cucumbers, the presence of bitter cucurbitacins. There may be good reasons to cultivate a taste for cucurbitacins, because recent studies have found that they may help slow the development of cancers. Bitter gourds are pale green, with an irregular, warty surface. They’re usually eaten while immature, sometimes after an initial blanching to remove some of the water-soluble cucurbitacins, and are either stuffed or combined with other ingredients, which moderate the bitterness. Mature fruits contain a red, sticky, sweet material that covers the seeds and is sometimes eaten.