The study provides an overview of the existing literature on the topics of colic, peritonitis and peritoneal lavage in horses as well as the use of peritoneal lavage in human medicine. As there are only few research results on peritoneal lavage in horses so far, the therapeutic procedure of postoperative peritoneal lavage, which was applied at the Klinik für Pferde (Chirurgie) mit Lehrschmiede der Justus-Liebig-Universität Gießen from 1995 to 2014, was examined in more detail through a retrospective study. In addition to the evaluation of the patient files, the patients’ owners were asked about the performance level, recurrent colic episodes and survival of the lavage patients. The study’s aim was to determine positive and negative effects of postoperative peritoneal lavage on the healing process and the efficacy of peritoneal lavage as adhesion prophylaxis. The collected values were examined and compared with literature values. In the years 1995 to 2014, 2452 colic patients were treated surgically at the Klinik für Pferde (Chirurgie) mit Lehrschmiede der Justus-Liebig-Universität Gießen. Of these colic patients, 563 were postoperatively treated with a peritoneal lavage. In these colic patients, contamination of the abdominal cavity had to be assumed due to ischaemia, rupture or surgical opening of the intestine. Postoperative peritoneal lavage was mainly used after displacements of small intestine into a hernia (21.3%), torsions of the colon (15.5%), displacements of the colon (11%), colonic impaction (10.5%) and strangulation by pedunculated lipoma in the area of the small intestine (8.3%). Small intestine diseases were treated slightly more frequently than diseases of the colon. Previous operations were enterotomies in 40.2%, resections in 31.1% and repositioning of displaced bowel sections in 27.9%. The decision for postoperative peritoneal lavage was made by the surgeon during the abdominal cavity operation. A Redon drain was inserted into the linea alba. In the postoperative period, every 12 hours NaCl infusion solution to which various additives were added (heparin, ampicillin, amoxicillin, lidocaine) was infused into the patients` abdominal cavity. The peritoneal lavage was well tolerated by the patients and complications related to the Redon drainage also occurred very rarely (7,2%). Postoperatively, colic symptoms occurred in 213/549 of the lavage patients and 25/549 patients suffered from suture dehiscence. The cell count of the peritoneal fluid, which increases in the first 48 hours after surgery, was reduced as a result of peritoneal lavage. Antibiotic supplements and heparin had an additional lowering effect, while lidocaine slowed down the decrease in cell count and led to significantly more patients with postoperative colic. Similarly, Horses receiving Ampicillin intraperitoneally were more likely to suffer from postoperative colic. 72% of the lavage patients were discharged cured and 79.7% of the discharged traceable lavage patients were still alive at least one year after discharge. 77.7% of the traceable lavage patients regained their original level of performance. Colic symptoms occured postoperatively in 38,8% of the lavage patients, which is a slightly higher frequency than that observed in other studies (28.2-33%) on complications after colic surgery (McCarthy und Hutchins 1988; Proudman et al. 2002; Mair und Smith 2005b). Suture dehiscence (4.6%) occurred much more frequently than in the other studies (1-3.8%) (van den Boom und van der Velden 2001; Gazzerro et al. 2015). Postoperative peritoneallavage reduces the cell count in peritoneal fluid. The geometric mean values of the cell count of the peritoneal fluid (increase up to 20.42 x 109 cells/l) also present lower than in studies without postoperative peritoneal lavage (242 x 109 cells/l) (Sapper and Gerhards 2005). Compared to human medicine, the risks to the patient associated with peritoneal lavage are significantly increased in horses. In addition, the material and personnel costs are higher. Nevertheless, in cases of severe manifest peritonitis, the success of peritoneal lavage outweighs the risks, which is why peritoneal lavage should be performed in these cases. The study does not allow clear conclusions on the use of peritoneal lavage for peritonitis and adhesion prophylaxis, which therefore needs further investigation.