What effect does Digitalis have on the body?

Digitalis is primarily known for its positive inotropic effect, which means that it increases the force of cardiac muscle contractions. This leads to an increase in cardiac output, making it particularly beneficial for patients suffering from heart failure or various heart rhythm disorders. By enhancing the efficiency of the heart's pumping action, Digitalis improves blood flow to vital organs, which can alleviate symptoms associated with congestive heart failure.

The other options relate to effects that are not characteristic of Digitalis. While Digitalis could potentially cause gastrointestinal symptoms like vomiting in some individuals, its primary and clinically significant action is related to cardiac output enhancement. It does not function as a laxative, nor does it have a primary role in increasing urination, as its main effect is on the cardiovascular system rather than the gastrointestinal or urinary systems. Therefore, the increase in cardiac output is a direct and essential reason for the use of Digitalis in medical treatment and patient care.