Digoxin is a cardiac glycoside extracted from the leaves of a plant called digitalis lanata. Digoxin is used to treat heart failure and abnormal heart rhythms (arrhythmias) and to slow the heart rate in patients with atrial fibrillation. It is a relatively safe, cheap and effective therapy for relieving recurrent symptoms in patients with congestive heart failure. Digoxin strengthens the heart by increasing calcium inside the cells of the heart. The heart can pump stronger and more effectively. Digoxin toxicity takes place when excess doses are consumed acutely or over an extended period of time. It is often divided into acute or chronic. The effect of digoxin therapy differs between men and women. Digoxin therapy is associated with an increased risk of death from any cause among women, but not men, with heart failure and depressed left ventricular systolic function.