Tonsillectomy and adenoidectomy remain the first choice treatment of chronic or recurrent acute infections of the upper respiratory tract in children. The aim of this study is to investigate the efficacy of the combination of thiamphenicol glycinate acetylcysteinate plus beclomethasone, administered as aerosol, in children awaiting tonsillectomy and/or adenoidectomy. The study comprised 204 children, aged 1 to 12 years, with chronic adenotonsillitis who had been listed for surgery due to obstructive symptoms and recurrent acute infections. Patients were randomized to treatment with thiamphenicol glycinate acetylcysteinate, dosage 250 mg/day in 2 administrations plus beclomethasone with a dosage of 400 microg/day in 2 administrations, or no treatment, control group, unless required. The drugs were administered by aerosol for 10 days/month over a period of 6 months. Clinical visits were at 4, 7 and 12 months after the start of treatment. The primary efficacy outcome was the reduction in the number of patients requiring surgery. Secondary efficacy measures were the reduction of nasal obstruction, the decrease in the number of infectious episodes and the tolerability of the treatment. Aerosol treatment with thiamphenicol glycinate acetylcysteinate plus beclomethasone resulted in a significantly lower proportion of patients requiring surgery (29 of 101; 29 percent) compared to patients in the control group (100 of 103; 97 percent) (p < 0.0001). Treatment was also associated with a reduction of nasal obstruction and a decrease in the number of infectious episodes. No treatment-related adverse events were reported and the aerosol therapy proved easy to administer to children. The aerosol therapy with the combination of thiamphenicol glycinate acetylcysteinate plus beclomethasone was able to prevent or postpone surgery in a substantial percentage of patients, without adverse events. These preliminary results suggest that this novel approach could play a role in the antibiotic prophylaxis of chronic infectious diseases of the upper airways.