Kaposi's sarcoma is a multifocal neoplastic process with four clinical variants, all of them induced by human herpes virus 8. Currently there is no treatment of choice and it depends on the extension and location of the lesions as well as on the clinical type of the disease. Alitretinoin gel 0.1 % is approved for the treatment of cutaneous lesions of AIDS-associated Kaposi's sarcoma. The majority of its side effects appear at the site of application and can lead to therapy withdrawal. We report a case of Kaposi's sarcoma treated with topical alitretinoin that had a favourable evolution in spite of an intense local reaction.