A cucurbit is a vegetable from the group of fruiting vegetable which is botanically classified among cucurbitaceous plants (Cucurbitaceae). The fruit is botanically called a berry and can be of different shapes from oblong, round, star-like and also square. The plant demands temperate climate, without bigger oscillations of temperatures. By the way of cultivation we can influence the content of primary and secondary metabolites in cucurbits. Nowadays the cucurbit is gaining the popularity. Among more known newer species are also butternut, moschata and hokaido cucurbits. They can be used as well in culinary as in medicine. The greatest part of the cucurbit is water and the rest is the dry substance. In the dry substance we find different primary and secondary metabolites. The primary metabolites are directly included in the processes in the plant, they represent the source of the energy for the plant. The secondary metabolites have no direct role in vegetal processes. They have an important ecological function, they serve as the protection from the herbivores and vegetal pests, they lure the pollinators, etc. They are very important in human nutrition. Among primary metabolites in the fruit of a cucurbit we find mostly starch, sugar, and grease in the seeds, from the secondary metabolites there are carotenoids, phenolics and aromatic substances. In all three described types of cucurbits we find different forms of carotenoids (zeaxanthin, lutein, alfa and beta carotene) which decompose during the storage and transform into new forms and give distinctive colours. The greatest amount of beta carotene rises just in time of storage. During the storage there is also the transformation of starch into more simple mono and disaccharides.