The effects of some neurosteroids on behavioral and hormonal markers of the naloxone-precipitated withdrawal syndrome in morphine-dependent mice were examined. 5 alpha-Pregnane-3, 20-dione inhibited dose-dependently the jumping behavior and the number of forepaw tremors, at a dose of 5 mg/kg it attenuated body weight loss; deoxycorticosterone acetate inhibited dose-dependently the jumping behavior and body weight loss, whereas dehydroepiandrosterone in a dose of 1 mg/kg prevented body weight loss, and in a dose of 20 mg/kg forepaw tremor. The other steroids tested had no significant effect on the morphine withdrawal syndrome. None of the neurosteroids influenced the increased plasma corticosterone level in the naloxone-precipitated morphine withdrawal syndrome. The above results indicate that 5 alpha-pregnane-3, 20-dione, deoxycorticosterone acetate and dehydroepiandrosterone, but not other neurosteroids tested, alleviate some signs of the morphine abstinence syndrome in mice.