The object of the invention is a coordination compound of platinum(II) as the cis-isomer with the formula I, to be used in therapy. The invention also relates to a method for producing a coordination compound of platinum(II) with the formula I, according to which the tetrachloroplatinate(II) compound and 6-aminoflavone are combined in a liquid hydroxylic solvent with a protection against light access, for 48-96 hours, at a temperature of 5-50°C, optionally with mechanical stimulation of the reaction environment and a coordination compound of platinum(II) is precipitated.