Isovanillin is a member of the class of benzaldehydes that is 4-methoxybenzaldehyde substituted by a hydroxy group at position 3. It is an inhibitor of aldehyde oxidase. It has a role as a HIV protease inhibitor, an antifungal agent, an antidiarrhoeal drug, an EC 1.2.3.1 (aldehyde oxidase) inhibitor, an animal metabolite and a plant metabolite. It is a member of benzaldehydes, a monomethoxybenzene and a member of phenols. Isovanillin is a reversible inhibitor of aldehyde oxidase. It is largely used as pharmaceutical intermediates and also applied in food and beverage industry, synthetic fragrances, chemical. Isovanillin is a selective inhibitor of aldehyde oxidase, is metabolized by aldehyde dehydrogenase into isovanillic acid ,and the LD50 (rat, ipr) is 1276 mg/kg.