Disclosed is a transdermal composition, which uses high-purity phosphatidylcholine that is most susceptible to oxidation and the like, and which exhibits high stability and high migration into the skin. Specifically, a transdermal composition having good stability and migration into the skin is able to be obtained by preparing a transdermal composition (a colloidal dispersion liquid of phosphatidylcholine) that contains high-purity phosphatidylcholine, carnitine, a polyhydric alcohol and water. Since the transdermal composition does not contain an oleaginous base (an oil component), the transdermal composition has skin compatibility and is thus useful as a therapeutic agent or a cosmetic preparation. In addition, phosphatidylcholine and carnitine have an effect of achieving good migration into the skin and are capable of promoting systemic or local lipid metabolism in subcutaneous adipose tissues. Consequently, the transdermal composition is able to provide a transdermal preparation that is capable of promoting lipolysis in subcutaneous adipose tisues.