An open comparative cross-over trial of the selective central M1 cholinoreceptors blocker - biperiden (akineton) was carried out in 35 patients with efedron encephalopathy (EEP) with mean illness duration 6,9 years. Patients received biperiden in individually adjusted dose, maximally up to 10 mg daily. Seventeen patients initially were treated with trihexyphenidyl in dosage 10 mg daily with switching to biperiden after 3 months. The total duration of treatment was 6 months. There was a significant decrease on the Fahn-Marsden scale and a clinical EEP scale, along with the moderate improvement quality of life assessed with the EQ-5D and the increase of the Barthel index. The decrease on the Fahn-Marsden scale by more than 30% was found in 40% patients treated with biperiden during 6 months and in 29% patients treated with trihexyphenidyl. Among patients switched to biperiden, 36% preferred to continue with the drug and only 12% preferred trihexyphenidyl.