Serum concentrations of testosterone (Tser), 5αL-dihydrotestosterone (DHT), estradiol 17β (E2), and free testosterone in saliva (Tsal) were determined by means of the radioimmunoassay method in 114 !Kung San men living in the Bushmanland district of Namibia. The healthy men (mean age 26.4 years) were asked about their dietary habits over the last two months and their acute alcohol intake during the 24 hours preceding the blood and saliva sampling. Although the sex hormone status of the !Kung lies within the range of normal men reported for Caucasoid samples, both Tser and Tsal exhibit relatively low concentrations in comparison to the great majority of published mean values. On the other hand, comparatively high DHT levels point to an elevated 5αL-reduction of testosterone to DHT in our sample. Estradiol concentrations show no deviation from normal values reported elsewhere for healthy young men. Different dietary habits of the !Kung lead to significant differences in their sex hormone status: both levels of Tsal and the androgen ratio Tsal/Tser decrease with increasing supplement of the traditional hunter-gatherer diet with domestic and Western food products. The amount of alcohol consumed during the day before the blood and saliva sampling shows a significant effect on the DHT metabolism, and the shorter the time after drinking, the greater decrease of DHT and DHT/E2 can be observed.