OBJECTIVE Therapeutic endoscopic techniques have changed the need for emergency surgery in gastrointestinal bleeding episodes. However, there is only little information about endoscopic therapies in severe gastrointestinal bleeding due to the Mallory-Weiss syndrome. The aim of this clinical study was to assess the usefulness of early endoscopic examination and sclerotherapy for severe or recurrent bleeding due to the Mallory-Weiss syndrome. METHODS We studied all 50 cases of gastrointestinal bleeding secondary to the Mallory-Weiss syndrome seen in 2175 consecutive emergency endoscopic examinations performed in a University Hospital over a 3-year period. Endoscopic sclerotherapy (1/10000 adrenaline + 1% polidocanol) was performed in all patients with active bleeding or visible vessel at endoscopic examination. The remaining patients were medically treated. RESULTS Active bleeding or a visible vessel were found in 13 patients; definitive hemostasis was obtained in all cases with sclerotherapy. The remaining 37 patients were successfully treated by conservative therapy. On admission, the severity of the hemorrhagic episodes was significantly higher in patients treated with sclerotherapy than in those who did not require this procedure. An esophageal perforation, successfully managed by conservative means, was the only complication recorded in the subset of patients undergoing sclerotherapy. CONCLUSIONS Severe bleeding due to Mallory-Weiss syndrome can be successfully treated by sclerotherapy. Early endoscopic examination is an accurate procedure in identifying patients who do not require sclerotherapy.