The activity of compounds of different structural types of aqua-complexes of the composition Cu(R-COO)2.nH2O-methoxybenzoatocupric complexes, R = 2-, 3- and 4-methoxyphenyl (n = 1, 1 and 3); aryloxyacetatocupric complexes, R = phenoxymethyl (n = 3), 2-, 3- and 4-chlorophenoxymethyl (n = 4, 2 and 2) and 1-naphthoxymethyl (n = 4), and furthermore isomeric furanecarboxylato-(R = 2- or 3-furyl, n = 3, or 1) and thiophencarboxylatocupric complexes (R = 2- or 3-thienyl, n = 1 and 1), was examined by the methods of the 1st screening on selected anthropo- and phytopathogenic microorganisms. The effects of all aqua-complexes (suspension dosage form) on the representatives of bacteria and yeasts are minimal. On the other hand, the effect of these substances on the causative agents of dermatomycoses (Trichophyton terrestre, Microsporum gypseum) in the case of methoxybenzoato- and furoatocupric complexes achieves a MIC value of 500 micrograms/cm3 and lower. The activity against phytopathogenic fungi (both in vitro and in vivo experiments) is generally relatively low at 0.05% concentration of active ingredients (dispersible powders). At the same time the antimicrobial activity of the pertinent free carboxylic acids was investigated in relation to the cupric salts being formed. They are able to form the required pharmacoactive form prevalently as late as they are in the form of aqua-carboxylatocupric complexes.