Phosphatidylcholine (PC), which has successfully been used in the past to increase ultrafiltration in continuous ambulatory peritoneal dialysis (CAPD) patients, has recently been found to prevent experimental adhesion formation after intraperitoneal irrigation with warm saline. The aim of this study was to determine the most effective route(s) of PC administration in the aforementioned model. Eighty Wistar rats underwent laparotomy and intraperitoneal irrigation with saline at 40 degrees C, which in 20 rats was followed by closure of the abdomen (control group, GC). In another 20 rats PC was given per os before and after irrigation (per os PC group, GOPC). In the third group PC was diluted in the irrigation fluid (intraperitoneal PC group, GIPC), and in the last group PC was given per os and intraperitoneally (combined PC group, GCPC). Assessment of adhesions was performed 2 weeks after the irrigation. Adhesions were found in 12 rats in the GC, 5 rats in the GOPC (p = 0.05, Fisher's test), 17 rats in the GIPC, and 3 rats in the GCPC (p = 0.007, Fisher's test). The difference between GOPC and GCPC was not statistically significant. The decreased adhesion formation after PC administration combined with the increased ultrafiltration may be of considerable importance in CAPD patients.