More and more veterinarians are going to perform laparoscopic diagnosis and surgery those days. But the technique using capnoperitoneum implicates several alterations of different physiological parameters, which, without proper monitoring, are often realized to late. Pathophysiology under CO2 insufflated abdomen as well as counter measures to keep or reestablish physiological situations are described. Within experimental studies, 27 pigs received partial colon resection using the laparoscopic technique, another six after laparotomy. They were compared concerning controlled ventilation, cardiovascular and blood gas parameters as well as the body temperature. Monitoring of the end-exspiratory CO2-gas tension as well as controlled ventilation seems to be essential. Blood gas analyses are proposed additionally. Under the described laparoscopic conditions blood circulation and body temperature seem to be influenced positively.