The in vitro biological activity of nine frequently used medicinal plants in South Africa was assessed and re-assessed after various lengths of storage. The plants investigated were Alepidea amatymbica, Leonotis leonurus, Drimia robusta, Vernonia colorata, Merwilla natalensis, Eucomis autumnalis,
Population growth, urbanization and the unrestricted collection of medicinal plants from the wild is resulting in an over-exploitation of natural resources in southern Africa. Therefore, the management of traditional medicinal plant resources has become a matter of urgency. In southern Africa the