CO2-pelviscopies or laparotomies were performed in 370 New Zealand white rabbits, and were followed by coagulation of the distal uterine horns with unipolar, bipolar, endo- or CO2-laser coagulation. After 1, 2, 4, 8 or 12 weeks laparotomy was carried out and, following macroscopic description, photo documentation and measurement of the destroyed region, the uterine horns were excised. In addition to the normal histological and electronmicroscopic evaluation, 5 µ thick cryostat sections were screened for the presence of nine different enzymes. Attempts were made not only to determine the extent of the destroyed zone, but also to obtain additional information on damage to the vascular and nervous systems of the tubes and ovaries. Progesterone levels were determined in 49 New Zealand rabbits before and after stimulation with 50 I.U. HCG i.v. We were able to show that there is a definite correlation between the type of coagulation technique and the extent of the destruction zone. The average progesterone levels of the animals coagulated using the monopolar high-frequency technique, were significantly lower than the hormone levels in the endocoagulation, bipolar or control group.