Abstract
Activity of the thyroid gland appears to be related to incidence of dental caries in the rat. These conslusions are based upon experimental observations that administration of desiccated thyroid reduces dental caries and thiouracil increases it. This cariogenic effect might be related to subsequent function of salivary glands, since it was shown that when desiccated thyroid and testosterone were given together it increases to a greater degree the anti-cariogenic effect of desiccated thyroid. This fact is in keeping with the observation that testosterone increases thyroid activity and that the thyroid gland is related to the function of the submaxillary gland.