Microcirculation and molecular biology are the hottest topics in modern surgical research. In familial adenomatous polyposis the incidence of carcinoma can be assessed by the localisation of the PAC-gene mutation. Restorative proctocolectomy with ileoanal pouch represents the procedure of choice. The optimal age for the operation varies between 20 and 35 years according to the localisation of the mutation. RT-PCR directed to recently defined surface antigens allows for the sensitive detection of intraoperative tumor cell liberation. Due to tumor cell detection in the systemic circulation the perioperative administration of monoclonal antibodies must be advocated. A preciser definition of lymphogenic tumor spread underlines the importance of systematic lymphadenectomy in resection of the colon. The understanding of microcirculatory disorders has optimized surgical decision-making intra- and perioperatively: function of renal and hepatic microcirculation is a reliable parameter to predict graft quality already intraoperatively and to monitor therapeutic approaches to ischemia/reperfusion injury. Results in the therapy of acute pancreatitis could be improved by operating less and later. Analysis of pancreatic microcirculation resulted in an improvement of ICU-therapy in the early stages of the disease. Transplantation of the liver is limited to hepatocellular carcinoma when its localisation or the residual hepatic function after resection preclude curative excision. In addition liver transplantation should not be carried out in tumors larger than 5 cm or in patients with more than 3 tumor nodules. Liver resection for colorectal metastases is a standard procedure. A second resection of recurrent metastases is advocated since an identical median survival can be achieved compared to the primary resection (32 mo). The surgical treatment of non-colorectal liver metastases is under evaluation and should be restricted to oncological centers. Special aspects of backwashileitis in ulcerative colitis will be outlined concerning timing of colectomy, pouch construction, and follow-up.