Crinum is an important Amaryllidaceous plant thanks to the valuable biological and therapeutic activities of its chemical constituents, especially alkaloids. Many Crinum species have been commonly used in traditional medicines worldwide. Long ago, they have been subjected to extensive chemical, cytological and pharmacological investigations. Accordingly, this work comprehensively comprises both the alkaloidal and non-alkaloidal principles of Crinums isolated from 1950 and up to now, together with various biological and toxicological studies conducted on both the total extracts and individual compounds. As being a major common class of Crinum alkaloids, the current part of this review work highlights the lycorine-type alkaloids isolated so far from this plant in addition to their distribution in different Crinum species.