The main links of cholera pathogenesis are surveyed. The noninflammatory nature of the toxic substance, a selective action of the cholera vibrio on the small intestinal epithelium and the absence of general toxemia are noteworthy. Cholera toxin (cholergen) produces an effect only in the small intestine mucosa where it interacts with some enzymic systems of the intestine, particulary adenylcyclase. This causes the secretion of a huge amount of isotonic fluid leading to marked disorders of fluid and electrolyte balance and considerable dehydration of the body. It is unwarranted to divide the disease into enteritic, gastroenteritic and gastric forms. A clinical classification of cholera into occult, mild, moderate and severe forms is suggested; an appropriate clinical symptom complex is given for each form.