A Cochrane review included 4 studies with 1943 patients with acute sinusitis. Both adults and children were included. Acute sinusitis was defined by clinical diagnosis and confirmed by radiological evidence or by nasal endoscopy. The trials studied intranasal corticosteroids (INCS) vs placebo or no intervention for 15 or 21 days; 3 trials as adjuvant therapy to antibiotics and one as monotherapy. Thee trials were combined in the meta-analysis. Patients with INCS were more likely to experience resolution or improvement in symptoms than those receiving placebo (73% vs 66.4%; RR 1.11; 95%CI 1.04 to 1.18). Higher doses of INCS had a stronger effect on improvement of symptoms or complete relief: for mometasone furoate 400 mcg vs 200 µg (RR 1.10; 95% CI 1.02 to 1.18 vs RR 1.04; 95% CI 0.98 to 1.11). No significant adverse events were reported. There was no significant difference in the drop-out and recurrence rates for the two treatment groups and for groups receiving higher doses of INCS.