Objective: To evaluate the efficacy and tolerance of azithromycin in the prevention of post-extraction alveolar osteitis (dry socket) in women according to their use of tobacco and oral contraceptives. Method and Materials: A clinical trial was conducted in 400 women who underwent tooth extraction, stratified into 4 risk groups according to their use of tobacco (yes/no) and oral contraceptives (yes/no). Each stratum (n = 100) was randomly divided into 2 groups: a study group that received azithromycin 500 mg once daily for 3 days after extraction and a control group that received physiologic saline 3 times daily from 24 hours after extraction for 7 days. Results: Azithromycin was significantly superior to conventional postextraction treatment with physiologic saline. There were no significant interactions with the use of either tobacco or oral contraceptives, and these variables had no confounding effects. Conclusion: Azithromycin is a safe and efficacious treatment for the prevention of dry socket in women. Keywords: alveolar osteitis, azithromycin, dry socket, orofacial pain, third molar extraction