The invention relates to a plaster containing an active agent, comprising at least one cover membrane and an active membrane which is based on a skin-compatible matrix containing a molecular sieve which is loaded with at least one active agent. The molecular sieve/active agent adduct releases the active agent when the active membrane comes into contact with the skin, in conjunction with the transpired water of the skin. The inventive plaster is characterised in that the molecular sieve/active agent adduct also contains water of crystallisation, to the extent that the molecular sieve is partially hydrated compared to a sufficient basic molar quantity (m) of water of crystallisation, the molecular sieve with the reduced molar quantity (m) of water of crystallisation being loaded with the active agent (Z, Z₁, Z₂) so that when the active membrane comes into contact with the skin, water is absorbed and the active agent is desorbed, whereupon the water of crystallisation content of the molecular sieve increases. The invention also relates to various suitable embodiments of the plaster containing an active agent and to an advantageous method for producing the inventive plaster containing an active agent.