In this randomized trial, 100 patients received ceftriaxone or amoxicillin-clavulanic acid in phlegmonous or abscess-forming ENT infections. Clinical and bacteriological results confirm that both antibiotics are equally effective, the advantage of ceftriaxone being one administration a day. Drainage surgery is necessary when an abscess has already formed. In 4 cases (ceftriaxone: 3; amoxicillin-clavulanic acid: 1), no positive response could be observed. Systemic and local tolerance was, as a general rule, excellent, and side effects were reported in 3 cases of the ceftriaxone group and in 3 cases of the amoxicillin-clavulanic acid group.