Adjuvant therapy may allow patients being treated with epoetin to derive greater clinical benefits. Iron supplementation is currently the most widely used form of adjuvant therapy; intravenous (i.v.) iron is required by the majority of haemodialysis patients receiving epoetin. Measurement of hypochromic red blood cells is the most direct way of assessing iron supply to the bone marrow. During the correction phase, a dose of i.v. iron equivalent to 50 mg/day is recommended, with the total dose not exceeding 3 g. When subclinical vitamin C deficiency is suspected, ascorbic acid may be given orally (1-1.5 g/week) or i.v. (300 mg three times weekly at the end of dialysis). The active vitamin D metabolites alfacalcidol and calcitriol may, under some circumstances, improve anaemia and reduce epoetin dosage requirements. Vitamin B6 requirements are increased during epoetin therapy, and supplementation at a dose of 100-150 mg/week is recommended. Supplementation of vitamin B12 is optional. Folic acid is supplemented routinely in haemodialysis patients, though evidence that it increases the efficacy of epoetin is limited. Low doses (2-3 mg/week) should normally be sufficient to maintain optimal folic acid stores in epoetin-treated patients, although higher doses are necessary for patients with hyperhomocysteinaemia. L-Carnitine supplementation may be appropriate in some patients with anaemia of chronic renal failure (CRF) unresponsive to, or requiring large doses of, epoetin. Androgens potentially could reduce epoetin costs in countries with limited resources, but should only be used in men older than 50 years with a remnant kidney. Recent animal studies indicate that the combination of epoetin and insulin-like growth factor 1 might be beneficial in CRF patients. High doses of angiotensin-converting enzyme (ACE) inhibitors should be reserved for dialysis patients who have hypertension that cannot be controlled by other agents, or who require an ACE inhibitor for treatment of heart failure.