This research was carried out mainly to investigate the effects of the aqueous extract and proteinous fractions of Aloe vera leaves on cholesterol, acetycholinesterase in brain, glycogen, glutathione in liver and malonaldehyde levels in heart in normal male albino mice. The antioxidant properties and inhibition of acetylcholine-sterase in tissue were detected. Intraperitoneal administration of Aloe vera extract in concentration of 400 mg/kg significantly decreased the levels of AchE in brain by (-88.27%) and glutathione content in liver by (-35.48%), and increased the levels of glycogen in liver and malonaldehyde in heart by (22.60%, 85.50%) respectively. At a concentration of 300 mg/kg Aloe vera extract significantly increased the level of cholesterol in brain by (24.39%). These results clearly show the antioxidant property of the extract of Aloe vera leaves.