The present invention provides a pipecolic acid derivative-containing liposome preparation having has an excellent rapid action capable of coping with an emergent situation such as cerebral infarction. A liposome preparation characterized by comprising, as an active ingredient, a pipecolic acid derivative of the ingredient described in the present specification or a pharmaceutically acceptable salt thereof entrapped into liposomes, wherein lecithin is mainly used as the liposome-forming lipid, said liposome preparation containing no cholesterol as a stabilizer.