A patch with stable transdermal absorbability, regardless of temperature changes during storage, in a crystallized formulation of clonidine is provided. This patch is characterized by including a backing, and a plaster layer integrally laminated on one surface of the backing, said plaster layer containing 5 to 30 wt% of clonidine containing crystallized clonidine, 25 to 90 wt% of a polymer base (A) having a viscosity average molecular weight of at least 800,000, and 5 to 60 wt% of a liquid additive capable of dissolving the clonidine, wherein the weight ratio of the liquid additive to the polymer base (A) [liquid additive/polymer base (A)] is 0.1 to 2.0.
