Digitoxin is primarily used in the treatment of heart conditions, particularly heart failure and certain types of irregular heartbeats (arrhythmias). It works by increasing the strength and efficiency of heart contractions, helping the heart to pump blood more effectively. This makes it beneficial for patients with weakened heart function. Additionally, digitoxin helps to control the heart rate in conditions like atrial fibrillation, ensuring a more regular rhythm. It is often prescribed when other treatments are not suitable or effective. However, due to its narrow therapeutic index, careful monitoring is required to avoid toxicity.