Abstract: Ruminant rumen has a detoxification to gossypol in diet, and there is no clinical symptom of poisoning after long application in production, but the existence and accumulation of a large number of gossypol in body will cause anti-ruminant nutrition and immunosuppressive effects to animals. Effects of gossypol on the metabolic turnover and physiological function of protein, iron and zinc as well as the immune inhibition of the breast were introduced in order to provide reference for how to avoid such side effects in the regulation of diets for dairy cows.