The invention relates to topically adminstrable pharmaceutical preparations containing pharmaceutically acceptable methanediphosphonic acid derivatives of formula ##STR1## and their salts, wherein each of R.sub.1 and R.sub.2 is halogen, or wherein R.sub.1 is hydrogen and R.sub.2 is Ar--S-- or Het.sub.1 --NH--, in which Ar is unsubstituted or substituted phenyl and Het.sub.1 is unsubstituted or substituted, monocyclic, 5- or 6-membered monoaza-, diaza- or thiaza-aryl that is bonded via a ring carbon atom, or wherein R.sub.1 is hydrogen or hydroxy and R.sub.2 is --A--R.sub.3, in which A is alkylene and, on the one hand, R.sub.3 is Het.sub.2, which is Het.sub.1 bonded via a ring carbon or ring nitrogen atom, or, on the other hand, R.sub.3 is hydrogen, or amino that is unsubsituted or mono- or di-substituted by identical or different substituents selected from alkyl, cycloalkyl, Ar-alkyl, Ar-O-alkyl, Ar-S-alkyl and Het.sub.1 -alkyl, or that is disubstituted by optionally Ar-containing alkylene, wherein two alkylene carbon atoms mar additionally be linked to one another via alkylene and Ar and Het.sub.1 are each as defined above, with the proviso that when R.sub.2 is --A--R.sub. 3, A is ethylene and R.sub.3 is unsubstituted or C.sub.1 -C.sub.3 alkyl-substituted amino, R.sub.1 is other than hydroxy.