To prevent a bone from a loss including the treatment and prevention of osteoporosis by administering a specific compound is combination with a bone absorption inhibiting polyphosphonate or a progesterone.

This osteoporosis treatment by simultaneous use of a polyphosphonate or a progesterone with an estrogen agonist, is to administer (A) a compound of the formula {A is CH2 or NR; B, D, E are each CH or N; Y is a (substituted) phenyl, a (substituted) naphthyl, a (substituted) 3-8C cycloalkyl, etc.; Z1 is (CH2)pW(CH2)q, etc., (W is CH2 or CH=CH; (p), (q) are each 0, 1-3); G is NR7R8 [R7, R8 each are phenyl or an (un)saturated 3-10C carbocyclic ring], etc.} and optical or geometric isomers thereof, and nontoxic and medicinally permissible acid adducts, N-oxides, esters and quaternary ammonium salts thereof in combination with (B) a bone absorption inhibiting polyphosphonate or a progestin. Further, the component (A) is preferably cis-6-(4- fluorophenyl)-5-[4-(2-piperidin-1-ylethoxy)-phenyl]-5,6,7,8-tetrahydronaphthalen-2-ol, etc.