Cardiac glycosides have been used for congestive heart failure and certain cardiac arrhythmias for more than 200 years. Despite the introduction of a variety of new classes of drugs for the management of heart failure, specifically angiotensin-converting enzyme (ACE) inhibitors, b-adrenergic antagonists (bblockers), and the aldosterone antagonist spironolactone, digoxin continues to have an important role in long-term outpatient management. However, a narrow margin exists between therapeutic and toxic doses of digoxin, resulting in a high incidence of digoxin toxicity in clinical practice.A wide variety of placebo-controlled clinical trials have unequivocally shown that treatment with digoxin can improve symptoms, quality of life, and exercise tolerance in patients with mild, moderate, or... severe heart failure. The clinical relevance of digoxin therapeutic monitoring is also proved but the SDC (Serum Digoxin Conentrations) required for optimal clinical efﬁcacy and acceptable toxicity remains controversial. In the last years, international guidelines recommend 1.2 ng/mL as acceptable high level.In this bibliographic synthesis, we aim to collect pertinent informations from MedLine database about exposure-effect relationship in order to assess the evidence level scientific of new digoxin therapeutic monitoring.