Digoxin molecule. Computer model of a molecule of the heart drug digoxin (C41.H64.O14). The atoms (balls) are colour-coded: carbon (blue), hydrogen (grey), and oxygen (red). Digoxin is a drug used to control irregular heart rhythms, and can also be used to increase blood flow in congestive heart failure patients. Digoxin is one of the drugs that is obtained from foxglove plants such as Digitalis purpurea.