Plants from the genus Physalis L. (family Solanaceae), native to warm and subtropical regions of Central and South America, are particularly rich in secondary metabolites, e.g.: withanolides, physalins, calystegines, tropane and nortropane alkaloids. Due to the high biological activities of these compounds, in the tropics Physalis plants have been used for centuries as medicinal herbs in the treatment of urinary and skin diseases, gonorrhea, ulcers, sores and as a vermicidal drug. This review describes the main categories of secondary metabolites, their distribution, chemistry, biosynthesis as well as biological activities. Particular attention is given to their potent anticancer activities.