Bismuth and its salts can cause kidney damage, although the degree of such damage is usually mild. Large doses can be fatal. Industrially it is considered one of the less toxic of the heavy metals. Serious and sometimes fatal poisoning may occur from the injection of large doses into closed body cavities (when used as medicine) and from extensive application to burns (in form of soluble bismuth compounds). It is stated that the administration of bismuth should be stopped when gingivitis appears, for otherwise serious ulceration stomatitis is likely to result. Other toxic results may develop, such as vague feeling of bodily discomfort, presence of albumin or other protein substance in the urine, diarrhoea, skin reactions and sometimes serious exodermatitis.

Bismuth is not considered a human carcinogen.

Bismuth toxicity from foods has not been described.