There is no recognized oral treatment for American cutaneous leishmaniasis. A rising-dose, open-label phase I/II trial of the oral agent miltefosine against Colombian cutaneous leishmaniasis was conducted. Seventy-two male Colombian soldiers (mean weight, 67 kg) received miltefosine at 50-100 mg/day for 3 weeks (for 32 evaluable patients) or at 133-150 mg/day for 3-4 weeks (for 32 evaluable patients). The per-protocol cure rate for 50-100 mg/day was 21 (66%) of 32 patients. The per-protocol cure rate for 133-150 mg/day was 30 (94%) of 32 patients (P =.01, by use of Fisher's exact test). The historic per-protocol cure rate for standard injections of antimony is 93%. "Motion sickness" that did not interfere with normal duties was experienced by 40% of patients and was dose related. Vomiting and diarrhea were reported on approximately 2% of treatment days. In this uncontrolled study of oral miltefosine for treatment of patients with American cutaneous leishmaniasis, a dosage of approximately 2.25 mg/kg/day for 3-4 weeks was effective and tolerated.