Adapalene is a useful new drug in the treatment of acne due to its tolerance and stability of effect. It is suitable in combination with other local and systemic drugs, e.g. antimicrobial preparations or benzoyl peroxide. After combined treatment and administration of adapalene alone the patients collaboration improves due to more comfortable use and much weaker irritant potential of this new substance. A number of authors confirm the reduced skin irritation. In the treatment of skin diseases some natural and synthetic retinoids are used. E.g. retinoic acid and one of its isomers, 13-cis retinoic acid (13-cis RA), are used as local and systemic drugs in acne. Considerable skin irritation caused by retinoic acid is the reasonwhy retinoids with a better relation between the therapeutic effect and side effects are sought. A modern chemical and pharmacological programme led to the discovery of a new synthetic retinoid, adapalene, which is effective and tolerated better by patients than retinoic acid. Pharmacological studies in vitro and in vivo provided evidence of the activity of adapalene as regards proliferation and differentiation of cells and tissues. Adapelene has also an anti-inflammatory effect which is due to its anti-AP1 action. It enters selective interactions with nuclear receptors RAR
and RAR and its effect on proliferation and differentiation can be blocked by the antagonist ofRAR
-.AsRAR
are not expressed inhumankeratinocytes, it is certain that the effect of adapalene on this main cellular type of epidermis is mediated by interaction with RAR. The unique pharmacological properties of adapalene explain - due to the improved tolerance - its better therapeutic effect as compared with tretinoin.

        Key words: