In this double-blind, parallel-group, multicenter study, 169 patients with symptoms of maxillary sinusitis but without radiographically confirmed empyema (pus) were randomly assigned to receive either 500 mg azithromycin once daily for 3 days (87 patients) or placebo daily for 3 days (82 patients). Nasal secretion, maxillary tenderness and pain, nasal obstruction, general malaise, and hyposmia were assessed at the start of the study and on days 4, 11, and 25 of treatment. After 11 days 58% of the patients in the azithromycin group were cured versus 31% in the placebo group; after 25 days the cure rate was 79% versus 67%, respectively. When both cure and improvement were considered, the corresponding figures after day 25 were 90% and 88%, respectively. Adverse events, predominantly gastrointestinal, occurred in 24 (27%) of the azithromycin-treated patients and in 15 (18%) of those treated with placebo, but the difference was not statistically significant. There was a difference in efficacy in favor of azithromycin in the treatment of rhinitis with symptoms of maxillary sinusitis but without radiological signs of empyema (pus). Antibiotics should only be used to alleviate symptoms in patients with moderate to severe symptoms, as the results after 25 days for both improvement and cure are equal. In the treatment of acute rhinitis with symptoms and signs of maxillary sinusitis but without empyema, treatment with azithromycin seems to result in a better cure rate after 10-12 days when compared with placebo.