The 5HT₃ receptor antagonist alosetron has been tested in several trials on irritable bowel syndrome (IBS) patients. The aim of the present meta‐analysis was to determine its effect on adequate relief of pain or global improvement of symptoms in IBS patients. Six large, multicentre, randomized, placebo‐controlled trials fulfilled pre‐set criteria for high quality and were included in the meta‐analysis; 1762 patients were randomized to alosetron treatment and 1356 to placebo. Seventy‐five per cent of the patients experienced diarrhoea‐predominant IBS and 93% were females. The pooled odds ratio for adequate relief of pain or global symptoms improvement was 1.81 [95% confidence interval (CI) 1.57–2.10). The average number of patients needed to treat with alosetron for one patient to achieve improvement over placebo treatment was seven (95% CI 5.74–9.43). The present analysis shows that alosetron 1 mg b.i.d. positively impacts global symptoms, and pain and discomfort in non‐constipated IBS female patients. One in four patients treated with alosetron may develop constipation. The efficacy of alosetron is unclear in male patients.