W14859 (liquid thrombin) was used to treat upper gastro-intestinal haemorrhage confirmed by endoscopy. Haemostatic effects were compared with those of topical thrombin. W14859 was administered directly under endoscopy and/or orally in 29 patients with upper gastro-intestinal haemorrhage. Haemostasis was achieved using direct application and subsequent oral thrombin in 17/19 (89.5%) cases, and direct or oral treatment alone in 4/6 (66.7%) cases. The efficacy rate was higher in non-transfused patients. In all 25 stomach biopsy patients, haemostasis was achieved within 60 s of directly applying W14859. There was no significant difference between the mean time taken by W14859 (17.7 ± 2.1 s) and topical thrombin (14.6 ± 2.0 s) and no adverse events were observed in any of the patients. It is, therefore, believed that W14859 can be routinely used in clinical practice.