The radioprotective action of a preparation from Hippophae rhamnoides berries RH-3, already reported to render >80% survival against whole body 10 Gy gamma irradiation, was further investigated with respect to the testicular system. RH-3 was administered to mice 30 min before gamma irradiation (5 and 10 Gy) and histological parameters such as testis weight, sperm count, frequency of abnormal sperm, repopulation index, stem cell survival index and seminiferous tubular diameter were assessed on the 35th day. RH-3 administration partially countered radiation induced reduction in testis weight, sperm count, repopulation index and stem cell survival index (p < 0.01). The increase in the frequency of abnormal sperm (15.17 +/- 1.046%) caused by irradiation (5 Gy) was counteracted by pre-irradiation treatment with RH-3, which significantly decreased the level of abnormal spermatozoa to 7.99 +/- 0.918% (p < 0.001), i.e. 52% abnormalities in comparison with 5 Gy irradiated group. RH-3 treatment alone did not elicit any toxic or adverse effect on the process of spermatogenesis. The present study suggests that RH-3 treatment protected spermatogenesis by enhancing the spermatogonial proliferation, enhancing the stem cell survival and reducing sperm abnormalities. The presence of polyphenolic flavonoids and tannins in the extract and the radical scavenging activity might be responsible for the radioprotective action of RH-3.