Three different regimens were compared for treatment of falciparum malaria in displaced Kampucheans living in encampments on the Thai-Kampuchean border in 1983: single dose 750 mg mefloquine, 1.5 g sulfadoxine, 75 mg pyrimethamine (MSP); 600 mg quinine 8-hourly for 3 days and 500 mg tetracycline 8-hourly for 7 days (Q3T7); or 600 mg quinine 8-hourly for 7 days and 500 mg tetracycline 8-hourly for 7 days (Q7T7). Radical cure rates were 98% (40/41) for MSP, 76% (32/42) for Q3T7 and 92% (33/36) for Q7T7. The criterion for treatment failure was reappearance of parasites by 35 days after commencement of treatment or no parasite clearance. Treatment failures comprised one case of reduction but no clearance of parasites (RII resistance) for MSP, 10 recrudescences (RI) for Q3T7 and 3 recrudescences (RI) for Q7T7. The radical cure rate for Q3T7 was significantly lower than that for MSP (P less than 0.01), whilst Q7T7 significantly from the other groups. Parasite clearance time was shorter (2.4 days) with MSP than with Q3T7 (3.5 days) and Q7T7 (3.3 days). There was little difference in side effects between the regimens, and tolerance was good. The MSP and Q7T7 regimens are both effective for treatment, but the single dose of MSP is much easier to manage than 7 days of quinine and tetracycline.