Leaves of L.leonurus were dried, ground and extracted separately using water and 1:1 methanol :dichloromethane resulting in aqueous and organic extracts. Both extracts were tested in an vitro biological assay against Mycobacterium tuberculosis method of Lall and Meyer(1999) . The organic extract showed greater than 99% growth inhibition when tested at 1000 ug/ml with the romanticism as the positive control 2 and was considered to have potent activity. The organic extract was subjected to fractionation by column chromatography over silica gel(Merck 5554