Background Acute laryngitis is a common illness worldwide. Diagnosis is often made by case history alone and treatment is often directed toward controlling symptoms. Objectives To assess the effectiveness and safety of different antibiotic therapies in adults with acute laryngitis. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1) which includes the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (January 1966 to January week 3, 2011), EMBASE (1974 to January 2011), LILACS (1982 to January 2011) and BIOSIS (1980 to January 2011). Selection criteria Randomised controlled trials (RCTs) comparing any antibiotic therapy with placebo for acute laryngitis. The main outcome was objective voice scores. Data collection and analysis Two review authors independently extracted and descriptively synthesised data. Main results Only two trials met the study inclusion criteria after extensive literature searches. One hundred participants were randomized to receive either penicillin V (800 mg twice a day for five days), or an identical placebo, in a study of acute laryngitis in adults. A tape recording of each patient reading a standardised text was obtained during the first visit, subsequently during re‐examination after one and two weeks, and at follow up after two to six months. No significant differences were found between the groups. The trial also measured symptoms reported by participants and found no significant differences. The second trial investigated erythromycin for treating acute laryngitis in 106 adults. The mean objective voice scores measured at the first visit, at re‐examination after one and two weeks, and at follow up after two to six months did not significantly differ between control and intervention groups. At one week there were significant beneficial differences in the severity of reported vocal symptoms as judged by the participants (P = 0.042). Comparing the erythromycin and placebo groups on subjective voice scores, the a priori risk ratio (RR) was 0.7 (95% confidence interval (CI) 0.51 to 0.96, P = 0.034) and the number needed to treat for an additional beneficial outcome (NNTB) was 4.5. Authors' conclusions Antibiotics appear to have no benefit in treating acute laryngitis. Erythromycin could reduce voice disturbance at one week and cough at two weeks when measured subjectively. We consider that these outcomes are not relevant in clinical practice. The implications for practice are that prescribing antibiotics should not be done in the first instance as they will not objectively improve symptoms.