Each year many people have digitalis toxicity severe enough to require extensive hospital treatment. Digoxin immune Fab[ovine]-Fab fragments (Digibind) have been shown to reverse digitalis toxicity and substantially reduce the risk of death. Data were used from uncontrolled studies of patients treated with Fab fragments as well as clinical, medical care and pharmacokinetic data from symptomatically treated patients to derive estimates of the difference in clinical outcomes and medical care costs when treating with this new drug. Estimates are derived separately for treatment of patients with toxicity that is immediately life-threatening and patients whose manifestations are not immediately life-threatening. Treatment with Fab fragments reduces the probability of dying more for the seriously toxic than for the less seriously toxic patient. Such treatment is generally associated with an increase in total medical care costs for the seriously toxic patients because more of them survive the toxic episode and require additional medical care before discharge from the hospital. For these patients, the estimated cost per life-year saved is between $1,900 and $5,400. When Fab fragments are used to treat less seriously toxic patients, total medical care costs decrease because of an estimated decreased number of days in the coronary care unit and decreased use of pacemakers and other aggressive treatments.