Method and apparatus for using computer controlled, fiber-coupled laser delivery of treatment specific wavelength, intensity and duration of UV irradiation to control bacterial, fungal, viral and mold infections in bodily cavities, fluids and external applications. The method of treatment is focused on DNA breakdown beyond repair by natural DNA repair mechanisms of the pathogen, with less than damaging doses to tissues being treated, thus avoiding mutagenicity and carcinogenicity. The minimal intensity and duration and exposure area of any given surface of tissue to be treated is to be pre-determined by tissue and pathogen testing to optimize the therapeutic ratio. External applications include specifically Trichophyton Rubrum (toenail fungus) through the nail and Pseudomonas Aeruginosa infections in burns and elsewhere.