To prevent intimal hyperplasia within a dialysis graft, a flexible tube comprising the dialysis graft is coated interiorly before placement with an anticarcinogen or mitosis-inhibiting agent for preventing cell division. The graft can also be irradiated with light energy by directing light into the lumen of the tube that has been grafted in place, thereby preventing or reducing dialysis graft intimal hyperplasia and reducing inflammation. The light source can be a light emitting diode (LED) or a chemical light source, i.e., a chemiluminescent substance for producing cool light energy within the graft to prevent or reduce the symptoms of GIH. When phototherapy is used, the body is exposed to light radiation at the site of the graft in sufficient amount to prevent undesired cell proliferation within the vessels, the graft, or surrounding tissue where the invention is used without detectable damage to body tissue.