Only oral and parenteral preparations in ATC group D are given DDDs. Most products in this group are for topical use, and no DDDs are assigned because the amount given per day can vary very much according to the intensity and distribution of the disease. Consumption figures for these dermatological preparations can be expressed in grams of preparations regardless of strength.

The DDD of betacarotene is based on the treatment of patients with erythropoietic protoporphyria.