Glutathione therapy was used for 2 months in a placebo-controlled double-blind cross-over trial of 20 infertile patients with dyspermia associated with unilateral varicocele (VAR) or germ-free genital tract inflammation (INF). The patients received either glutathione (group 1) or placebo (group 2) for 2 months, then they crossed over to the alternative treatment for a further 2 months. The patients were randomly and blindly assigned to treatment (one i.m. injection every other day of either 600 mg glutathione or an equal volume of a placebo preparation). The standard semen analysis and the computer-assisted sperm motility analyses were carried out before treatment and during the trial. Statistical cross-over analysis, case-control study and treatment efficacy test were carried out on groups 1 and 2 and differences in the effects of therapy between VAR and INF patients with varicocele or inflammation were tested. Glutathione therapy demonstrated a statistically significant positive effect on sperm motility, in particular on the percentage of forward motility, the kinetic parameters of the computerized analysis and on sperm morphology. The findings of this study indicate that glutathione therapy could represent a possible therapeutical tool for both of the selected andrological pathologies.