BACKGROUND: Epidural steroid injections (ESI) have been used widely for the treatment of back and radiating extremity pain. Although its effects on the metabolic and endocrine system have been studied, the effects following repeated injections remain to be determined. We studied the effects of three repeated caudal epidural injections of low dose triamcinolone. METHODS: The subjects were 10 elderly women with spinal stenosis. Caudal epidural injections were performed biweekly. Triamcinolone (20 mg), mixed with 15 ml of 0.25% lidocaine, was used as the ESI injectate. The procedures were performed with the patient in the prone position. Blood sampling was performed just before the first injection, and used as the baseline, and then just before each injection on the same day of the 2nd and 4th weeks, with the last samples taken 2 weeks after the third injection. RESULTS: The blood glucose concentrations showed no significant changes. The blood cortisol and ACTH concentrations were significantly decreased after the first injection, but there were no further decreases after each of the subsequent injections. The cortisol concentrations were maintained within the normal range. CONCLUSIONS: Caudal epidural injections, with low dose triamcinolone, suppressed the hypothalamus-pituitary-adrenal (HPA) axis, but no further suppression followed the subsequent repeated injections. Three consecutive caudal injections at 2 week intervals seems to be a safe procedure.