In the experiment on the 36 mature rats, the peculiarities of morphological disorders in the lower jaw of rats under the influence of salts of chromium, lead, zinc, iron, copper, and manganese are showed. Profound morphological changes in bone and cartilaginous tissues of lower jaw are followed by disorders of bone mineral content. The importance of the S100 protein in morphological changes in bone and cartilaginous tissues under the influence of heavy metal salts is shown.