The review summarizes research results on the use of oxalic acid as an acaricide in honey bee colonies. Three different treatment techniques (i.e. trickling, evaporation and spraying) have been developed for the application of oxalic acid. Detailed information is given on the efficacy against Varroa destructor, tolerability by Apis mellifera, protective procedures for the user, residue situation and consumer safety, as well as recommendations for use.