Natural O-methyl ether of myo-inositol, ononitol, (+)- is present, albeit in small amounts, in many plant families. For example, it was identified in pea (Pisum sativum L.) root nodules, in Cassia tora L. leaves, in leaves of Sesbania aculeate, Medicago sativa and others. In in vivo study, ononitol monohydrate decreased the levels of serum transaminase, lipid peroxidation and TNF-alpha but increased the levels of antioxidant and hepatic glutathione enzyme activities. Histopathological results also suggested the hepatoprotective activity of ononitol monohydrate with no adverse effect. Hence it was concluded that ononitol monohydrate is a potent hepatoprotective agent. Also, ononitol could be used as an agent to prepare botanical new pesticidal formulations.