This article deals with further development of laser drug delivery methods. In order to estimate the effect of laser- drug interactions, we carried out the chromatographic fractionation of dexamethasone, hydrocortisone, and gentamicine, both prior to and after irradiating them by pulsed Er:YAG laser radiation. The laser radiation parameters were as follows: the wavelength, pulse energy, and pulse duration were, respectively, 2.94 micrometers , 0.7 J, and 100 microsecond(s) . The total laser radiation dose administered to a 100 (mu) l sample of these drug preparations amounted to 150 J. A chromatographic analysis revealed that drug samples exposed to Er:YAG laser radiation did not show any change. The results obtained made it possible to employ pulsed Er:YAG laser radiation to perform laser-acoustic injection of the above-mentioned drug preparations to study the treatment of staphylococcal lesions in 30 guinea pigs. The perforated channel depth was measured and the injected drug solution volume was calculated. It was found that laser injection enabled one to introduce therapeutic doses of drugs, and that it expedited the healing of lesions by 3 to 4 days, as compared to the control group that received the topical application of drugs without laser irradiation.