Tentative estimates suggest that one in ten patients suffers from an adverse event in hospital. In Germany, approx. 1.8 million out of approx. 18 million inpatients suffer from adverse events; 50 percent of these cases are estimated to be avoidable. In the US, nearly 100,000 people die from the consequences of mistreatment. The intensive care units record 1.7 medical errors per patient and day. The most affected disciplines are the operative disciplines, particularly general surgery. Medical errors mainly occur when the indication for surgery is being made, during surgery and post-surgery. Suspicious oncological diagnostic results and post-operative complications are also often ignored. This book deals with complications and typical medical errors in surgery. It shows solutions and ways of dealing effectively with these errors and how to establish an efficient security management system.