Out of 938 parasitologically confirmed patients with visceral leishmaniasis treated with amphotericin B (1 mg/kg bodyweight daily infused in 2 h for 20 days), 935 were cured clinically, 933 parasitologically and 931 ultimately (no relapse within 6 months). Two parasitologically 'not cured' and 4 relapsed patients were cured with 25 infusions, and 1 with double relapse with 30 infusions. The treatment was started only when serum haemoglobin reached 5 g/dL, serum electrolyte imbalance was corrected and sodium stibogluconate-induced myocardial damage stabilized after 10 days' rest. Bronchopneumonia, cardiac failure and acute renal failure caused the death of 1 patient each. Nightblindness, angular stomatitis, neuritis, and petechial haemorrhages improved with appropriate treatment; 2 patients were given blood transfusion for post-treatment anaemia. Nausea and anorexia, and changes in serum creatinine and potassium, became normal in 2 weeks. Immediate withdrawal of the drug and restart after 10 days cured 2 patients who developed acute renal failure. Infusion-related toxicities--shivering, rigor and fever--were minimized but not eliminated by prior administration of hydrocortisone. Tuberculosis and visceral leishmaniasis were treated concurrently. Four pregnant patients were successfully treated without harmful effects on mother and child. It was concluded that the dosage of amphotericin B used was an effective and well-tolerated regimen and achieved 99% cure. Toxicity could be minimized with some precautions. All unresponsive and relapsed patients responded to more amphotericin and no resistance to the drug was seen.