At the same time, the nature of the effect of the toxicant is determined not only by its chemical properties and dose in the initial state, but also by its intermediate and final metabolic forms. Metals and their compounds, unlike many organic compounds, can repeatedly change their form when they enter the body.Conclusions. Experimental studies of the influence of heavy metals on the morphology and physiological state of the digestive system with the determination of possible mechanisms of intoxication are an urgent problem for morphological research.