Mycophenolic acid is effective for systemic treatment of psoriasis. However, there is no report about its topical use in this cutaneous disorder so far. We undertook a randomized, placebo-controlled, within subject comparison of mycophenolic acid 1% incorporated in an ointment base and the corresponding vehicle alone (placebo) using the psoriasis plaque test in 7 patients with plaque-type psoriasis over a period of 3 weeks. Scoring of erythema and induration was performed 3 times weekly. After 3 weeks of occlusive treatment there was a reduction of the sum score for erythema and induration in the mycophenolic acid-treated sites of 23% and of 5.7% in the vehicle-treated sites, which was not statistically significant. No adverse advents were noted during the time of study. We conclude that mycophenolic acid is ineffective when applied topically in psoriasis even under occlusion.