PURPOSE: To provide the titled plaster capable of keeping the drug stably without decomposition, by compounding butylhydroxytoluene and a gallic acid ester to a plaster composed of a rubber-based adhesive material.

CONSTITUTION: A plaster composed of a rubber-based adhesive material such as natural rubber, synthetic rubber, and their mixture optionally added with a tackifier, an agent for regulating the adhesivity and holding power, a filler, etc., is incorporated with 0.002W5wt% of butylhydroxytoluene and 0.005W5wt% of a gallic acid ester (preferably 1W8C alkyl ester, especially n-propyl ester). When a drug applicable to the skin is added to the plaster, an adhesive salve preparation free from the loss of the drug in the plaster with time can be obtained. The above composition is especially effective when the drug is a compound containing phenolic OH or an amine compound.