Abstract: A device suitable for the topical administration of a pharmacologically active agent to an animal is described. The device comprises an active agent impermeable barrier layer, a reservoir containing the active agent which is in contact with the inner surface of the barrier layer and a removable protector layer in contact with the other surface of the reservoir. The reservoir comprises a fibrous mat into which the pharmacologically active agent is incorporated either by dissolving in the polymer forming the mat or by impregnation of a preformed mat. Alternative forms of the reservoir comprise a fibre mat coated on a skin contacting surface with a pressure sensitive adhesive and a fibre mat contained within a gel matrix. The device may be used to deliver nitroglycerin, oxybutynin or phenazocine transdermally.