The present invention provides a transdermal absorptive liquid preparation in which a medicament or a salt thereof is colloidally dispersed in propylene glycol or a propylene glycol-containing solvent, whose transdermal permeability of the medicament is excellent, problem of skin irritation is reduced. The liquid formulation of the present invention has a mode of particle diameter at around 100nm, and an average particle size of 50 to 500 nm. The liquid formulation of the present invention makes marked improvement in the transdermal permeability by further containing an absorption promoter such as triethanolamine.