Abstract This study investigated the in vivo effect of Diosgenin, isolated from Asparagus officinalis, on the total quantity of Cytochrome P450, the activity of some enzymes – Ethylmorphine N-demethylase (marker for CYP3A) and Aniline Hydroxylase (marker for CYP2E1), the quantity of malondialdehyde and reduced glutathione compared to Phenobarbital in rats. Diosgenin and Phenobarbital, administered alone, increased statistically significant, compared to control, the total amount of Cytochrome P450 – with 36 % and with 85 %; the activity of EMND with 58 % and with 184 %. Diosgenin didn’t influenced the AH activity compared to Phenobarbital. Both Diosgenin and Phenobarbital had no statistically significant effect on GSH level. On the quantity of MDA, Diosgenin had no effect, while Phenobarbital increased it with 27 %. Our results showed that Diosgenin exhibited inducible effect similar to the effect of Phenobarbital on the activity of some drug-metabolizing enzyme systems.