The present invention provides a medical adhesive tape and a tape preparation for percutaneous absorption, both having an adhesive layer that resists glue remainder and stickiness upon peeling off of the tape even after adhesion to the human skin for a long time, and a medical adhesive composition to be used for such tapes. The medical adhesive composition of the present invention includes, as essential elements, (A) a copolymer containing (a) alkyl (meth)acrylate, wherein the alkyl moiety has 4 to 18 carbon atoms, in a proportion of not less than 50 wt % of the copolymer and (b) a carboxyl group-containing vinyl compound in a proportion of 0.1 wt % 10 wt % of the copolymer, (B) an alkoxide or a chelate compound of at least a metal selected from titanium, zirconium, zinc and aluminum, and (C) a polyol compound in a proportion of 0.2 wt % 5 wt % of the aforementioned medical adhesive composition. The medical adhesive tape of the present invention and tape preparation for percutaneous absorption are characterized in that the adhesive layer contains the above-mentioned medical adhesive composition of the present invention.