In a clinical trial on 220 patients with bacteriologically proved enteric fever trimethoprim-sulphamethoxazole was compared with chloramphenicol. All patients in both groups responded, and the mean periods of defervescence after starting therapy were similar in both groups. Trimethoprim-sulphamethoxazole was much superior to chloramphenicol in rapidity and uniformity of relief of toxaemia. "Toxic crisis" occurred in 10 out of 120 patients in the chloramphenicol group and was absent in the trimethoprim-sulphamethoxazole group. No major side-effects due to specific drug therapy were observed in either group.