||The cytotoxicity and an in vitro antiamoebic effect of Senna didymobotrya (Irwin Fresen) were studied. 300g of crushed S. didymobotrya was isolated in several solvents namely Dichloromethane, ethyl acetate, methanol, hexane and water extracts. The minimal inhibitory concentration (MIC) and IC50 of the extracts in comparison with metronidazole were then obtained on trophozoite of E. histolytica, HM-1: IMSS strain in LYI-S-2 medium. The MIC for S. didymobotrya dichloromethanolic, methanolic successive, hexanic and water extracts after 48 hours was 500mg/ml each while methanolic total had a MIC of 250mg/ml. MIC for metronidazole was 62.5mg/ml whereas ethyl acetate was inactive. The IC50 for S. didymobotrya dichloromethanolic, methanolic total, methanolic successive, hexanic and water extracts was 2.15, 3.63, 0.3, 0.46, 0.12 and 0.58 respectively. The IC50 for metronidazole was 0.03. Senna didymobotrya is effective on the trophozoites of E. histolytica species and the methanolic total extract exhibited the greatest antiamoebic activity, at the lowest MIC.