Résumé : One hundred and seventeen inpatients and outpatients with primary degenerative dementia participated in a multicentre, placebo‐controlled, parallel‐group, therapeutic study with CBM 36‐733 (2‐methyl‐alpha‐ergokryptine) lasting eight weeks. The daily dose of CBM 36‐733 was 2.0 mg, after a slow increase over 10 days. The assessment of effects relied on factors derived from the SCAG (Sandoz Clinical Assessment Geriatric) scale and the NOSIE (Nurses' Observation Scale for Inpatient Evaluation), a battery of pscyhometric tests, and overall evaluation of efficacy and tolerability (plus laboratory analyses). CBM 36‐733 was well tolerated and positive changes were seen with regard to the ‘Apathy’ factor of the SCAG scale and in psychometric tests measuring psychomotor speed, attention, and some aspects of memory. Longer‐term studies are now required to determine the clinical relevance and duration of improvements that can be achieved with CBM 36‐733 in patients suffering from primary degenerative dementia. Copyright © 1988 John Wiley & Sons, Ltd.