The present invention provides a method andcomposition for promoting hair growth in a mammal whichcomprises a prostaglandin compound of formula (I)(see formula I)wherein L, M and D are hydrogen, hydroxy, halogen,lower alkyl, hydroxy(lower)alkyl, lower alkanoyloxy or oxo,wherein at least one of L and M is a group other thanhydrogen, and the five-membered ring may have at least onedouble bond；A is -CH3, or -CH2OH, -COCH2OH, -COOH or a functionalderivative thereof；B is -CH2-CH2-, -CH=CH- or -C.ident.C-；Z1 and Z2 are oxygen, -NH- or sulfur,R2 and R3 are optionally substituted lower alkyl,which is optionally linked together to form lower alkylene,R1 is a saturated or unsaturated bivalent lower ormedium aliphatic hydrocarbon residue, which isunsubstituted or substituted with halogen, alkyl, hydroxy,oxo, aryl or heterocyclic group, and at least one of -CH2-group in the aliphatic hydrocarbon is optionallysubstituted by oxygen, -NH- or sulfur； andRa is a saturated or unsaturated lower or mediumaliphatic hydrocarbon residue, which is unsubstituted orsubstituted with halogen, oxo, hydroxy, lower alkoxy, loweralkanoyloxy, cyclo(lower)alkyl, cyclo(lower)alkyloxy, aryl,aryloxy, heterocyclic group or heterocyclic-oxy group；lower alkoxy； lower alkanoyloxy； cyclo(lower)alkyl；cyclo(lower)alkyloxy； aryl； aryloxy； heterocyclic group； orheterocyclic-oxy group,as an active ingredient thereof.
