BACKGROUND: Acute exacerbations of chronic bronchitis (AECB) are the mostcommon complication of chronic bronchitis. The majority of AECB are caused by infection. The choice ofappropriate antibacterial therapy for AECB is becoming more difficult and is usually empirically. Cefaclorand cefuroxime are used for ambulatory treatment of AECB. MATERIAL/METHODS: This multicenter, randomized,single blind study was undertaken in order to compare efficacy and safety of cefaclor AF (500 mg BID)and cefuroxime axetil (250 mg BID) in 10 days treatment of ambulatory patients with AECB. 170 adultswere enrolled into the study. Clinical responses were assessed on 17th-24th day after randomization.RESULTS: Both antibiotics had high over 97% effectiveness in the treatment of AECB. There was statisticallysignificant 1.7 times higher rate of patients with cough release after cefaclor treatment compared tocefuroxime (p

Keywords: Aged, 80 and over, Bronchitis, Chronic, Cefaclor, Cefuroxime, cephalosporins, Comparative Study, Single-Blind Method, Time Factors