All sources however, agree that ripe seeds may be popped or variously used in cookery. They then are pleasant and nutritious, but require a lot of work to harvest and strip from the fruit capsule. To some extent this may be circumvented rotting the fruit under water for three weeks or more, after which removing the seeds is easier. The rotting material however, is very unpleasant to deal with. The flower petals are said to be used in making tea, but it is not clear whether that refers to the petals proper, or to the larger and more conspicuous sepals. The leaves of some species are large enough to be of use in wrapping food, for example in cooking. Alkaloids in the genus include nupharolutine, nuphamine and nupharidine. The presence of such compounds could explain some of the medicinal uses  There has been growing interest in "Nuphar" alkaloids, their biological and pharmacological significance and their synthesis in recent decades. It has been speculated that these and other bioactive compounds might be related to some of the folk-medical applications of the plants. Apart from pharmaceuticals, the leaves of "Nuphar" are reported to contain sufficient concentrations of tannin to have been widely used for tanning and dyeing leather, and also as a styptic for staunching bleeding. The roots of some species also contain sufficient tannin to have been used for tanning.