In a double-blind, controlled randomized trial, 88 adult patients with acute diarrhea (more than three watery stools per day) received either 400 mg of nifuroxazide twice daily or placebo for 5 days. The mean duration of diarrhea in the nifuroxazide group was 2.09 days versus 3.26 days in the placebo group (p less than 0.004). The number of bowel movements per day diminished and mucus disappeared more quickly in patients treated by nifuroxazide than in patients of the placebo group. Nifuroxazide was well tolerated and no side effects were observed. Nifuroxazide is an effective therapy for acute diarrhea and can be prescribed from the onset of diarrhea without waiting for stool culture results which can be late or negative.