Postoperative adhesions account for a significant morbidity after abdominal, gynecological, or cardiac surgery. A large number of compounds have been suggested to prevent such adhesions, but none is generally accepted. We have compared eight different substances that could be beneficial for the prevention of postoperative adhesions in a new standardized rabbit model with measurement of the areas of adhesion. In 10 groups of 20 rabbits an area of abrasion of the serosa of the ileum, the appendix, and the abdominal wall measuring 10,000 mm2 was created by an emery piston during celiotomy. The controls received no medication. The treatment groups received a single intraperitoneal administration of 1 ml per 100 g body wt of normal saline (NaCl), 5 mg taurolidine (T), 0.5 U plasmin/300 U DNase (PD), 2000 IU streptokinase/500 IU streptodornase (SS), 7 mg phosphatidylcholine (PC), 4 mg hyaluronic acid (HA), 7 mg sphingolipid (SL), 7 mg galactolipid (GL), or 0.5 ml tetrachlorodecaoxide (TCDO), respectively. Ten days later the extent of adhesions was quantified by morphometry. The total area of adhesions (+/- SEM) was found to be 1998 +/- 124 mm2 in controls. The application of NaCl reduced the adhesions to 1368 +/- 58 mm2, of T to 1012 +/- 48 mm2, of PD to 673 +/- 33 mm2, of SS to 360 +/- 44 mm2, of PC to 335 +/- 84 mm2, of HA to 328 +/- 76 mm2, of SL to 278 +/- 80 mm2, of GL to 261 +/- 67 mm2, and of TCDO to 240 +/- 45 mm2. The effects of PD, SS, PC, HA, SL, GL, and TCDO were significant in comparison to controls and NaCl. Our experimental data suggest that the two new lipid substances, SL and GL, are the most likely candidates for routine clinical use in the prevention of postsurgical adhesions.