The use of extracts from Cryptolepis sp. or quindoline alkaloids such quindoline and cryptolepine contained therein as hypoglycemic agents, as well as methods for obtaining the hypoglycemic agents are described. According to a preferred embodiment, the extracts are derived from Cryptolepis sanguinolenta. As hypoglycemic agents, the extracts or quindoline alkaloids such as quindoline or cryptolepine are useful for treating insulin-dependent (type I) and non-insulin-dependent (type II) diabetes.