It is the purpose of this paper to describe the results of therapy as observed in patients with erosive lichen planus of the oral mucous membranes through the use of a topically applied corticosteroid, triamcinolone acetonide, incorporated in a new adhesive vehicle,1 the latter having been specifically designed for the more efficient application of therapeutic agents to oral mucous membranes. Triamcinolone acetonide2,3 (Kenalog), a synthetic corticosteroid derived from triamcinolone, has been observed to be a particularly active and useful topical agent, although it is also an active corticosteroid when administered systemically.4 Methods Twenty patients, including 7 men and 13 women, aged 33 to 56, treated for erosive lichen planus of the oral mucosa, are the subjects of this report. All patients had been treated previously with one or more therapeutic agents, including, but not restricted to vitamins, sex hormones, placebos, other corticosteroids, and mouth washes, but without