[The oxidation behavior of dithranol].

When Dithranol is oxidized in a weakly alkaline buffer by air oxygen one has to discuss two different oxidative pathways. Under homogeneous conditions (dithranol dissolved) the only oxidation product is dithranol-dimer (and subsequently dithranol-brown) whereas under heterogeneous conditions (dithranol suspended) mainly chrysazine (dantron) is produced, which does not alter under the chosen conditions. These circumstances may play an important part in the dithranol therapy of psoriasis.