This book is based on the research that aimed at investigating the in vitro antioxidative potentials and membrane stabilization potentials of Kigelia africana stem bark extract and its fractions on bovine red blood cell membrane. This was with a view to study its potentials against reactive oxygen species. As the result of this investigation, the methanolic extract and fractions of stem bark of Kigelia africana possess antioxidative potentials and membrane stabilization potentials with the highest activities ascribed to the ethyl acetate fraction of the plant. This may offer some beneficial effects in the management of inflammatory condition and vascular diseases generated from the reaction to oxygen species.