Nitric oxide (NO) plays an important role in modulating blood flow in normal and in several pathological conditions, and its levels seem to change with ischemia-reperfusion injuries. Caffeic acid phenethyl ester (CAPE), an active component of propolis, exhibits antioxidant properties. This experimental study was designed to determine the changes in NO levels and the effect of CAPE on NO levels after testicular torsion/ detorsion in rats. Thirty-five adult male albino rats were divided into four groups: sham operation (n = 8), torsion (n = 9), saline/detorsion (n = 9), and CAPE/detorsion (n = 9). Rats in the sham operation group were killed after the testes were handled without torsion. Rats in the torsion group were killed after 720 degrees clockwise testicular torsion for 2 h. CAPE was administered 30 min before detorsion in the CAPE/detorsion group and saline was administered in the saline/detorsion group. After 4 h of testicular detorsion in both of these groups, the rats were killed and bilateral orchiectomy was performed to determine the tissue levels of NO. The level of NO in the torsion group (113.77 +/- 33.18 nmol/g protein) was significantly higher than that of the sham operation group (64.53 +/- 29.64 nmol/g protein). In the saline/detorsion group, the NO level (31.26 +/- 12.58 nmol/g protein) was significantly lower than in the torsion and sham operation groups. CAPE administration in the CAPE/detorsion group seemed to raise the NO level (72.63 +/- 23.87 nmol/g protein) above the level of the sham operation group. Contralateral testes were not affected by the torsion/detorsion processes performed on the ipsilateral testes. These results show that NO levels increase with torsion and decrease with detorsion. CAPE administration seems to increase tissue NO levels and this may be important for protecting the testes from torsion/detorsion injuries.