This analysis of visceral medical claims from 2000 - 2009 of the Arbitration Agency for Questions of Medical Liability of the North German Chamber of Physicians can offer advice for error prevention and quality assurance. It provides information on concerned patients and physicians, reproach behaviour, fault priorities and liability. The latter is given in treatment-related error-caused damage (substantiating liability causality 1). Causality is liability excluding if the damage is related to treatment, but not error caused (causality 2) or disease caused (causality 3). 2.763 visceral medical damage cases were selected from 26.474 arbitration cases of the mentioned 10 years by means of ICD-10 codes. Differentially often they concerned almost all medical specialties. In patients affected the peak incidence was at equal gender proportions in the second half of working age. The intestine was affected most often. The 2763 claims accounted for 5.530 patient's reproaches. At 61 % error-free cases 1954 established treatment errors distributed to 39 % of faulty cases. 840 (30 %) cases corresponded to liability establishing causality 1. Of these 363 (43 %) cases with faulty operational measures were listed only for comparative purposes. Extensively studied were 345 (41 %) cases with faulty conservative measures and 132 (16 %) cases with errors in connection with endoscopic measures. The conservative measures group most commonly affected was with 52 % diagnosis, general diagnostics, medical history, physical examination as well as differential- and further diagnosis accounted for 20 % each. In 66 % omissions and in 34 % faulty implementation had caused damage, 77 % of a transient nature, 16 % permanent and 7 % fatal. In the context of endoscopies 58 % faulty implementations and 42 % omissions had led to 60 % with transient damage and to permanent and fatal damage in 20 % each. Only one quarter of the errors concerned the endoscopic examination itself, three quarters concerned accompanying measures, most frequently complication management. Claims were well founded in 30 % of the arbitration cases, 15 % of patient's reproaches and 43 % of treatment errors. The results allow the encouraging knowledge that most error-caused damage did not occur in the complex, technically sophisticated medical interventions but rather were caused by avoidable failures in daily clinical and practical routine, and therefore could be prevented.