Photodynamic therapy (PDT) uses light and a light-sensitive dye to treat active acne. It is also being tested for the treatment of bacterial infection and skin conditions such as psoriasis. During the procedure, a photosensitized dye or drug is applied to the problem area, which is then exposed to pulses of a narrow-wavelength beam of laser light. The dye absorbs this light and produces an active form of oxygen that aids in shrinking oil glands and temporarily reducing oil production. PDT ensures high precision by targeting only the tissue in and near the treatment area.