Rifampicin re-administration may cause immunologically mediated acute tubulo-interstitial injury. Retrospectively, 170 consecutive cases with acute renal failure (ARF) following re-treatment with rifampicin (71% males, 29% females, age 21 to 68 years) were analysed, which accounted for 12% of all ARF patients treated by two large dialysis referral centres in Romania, Timisoara and Iasi, between 1974-2001 and 1988-2001, respectively. The most frequent clinical features of rifampicin-induced ARF were: Anuria, gastro-intestinal (abdominal pain, nausea, vomiting and diarrhoea) and "flu-like" symptoms. Urine analysis revealed sterile leucocyturia in 54%, proteinuria in 31%, haematuria in 26% and haemoglobinuria in 7% of cases. Haemolytic anaemia was frequent, found in 66% of the patients; half of these had Hct values of < 30%, thrombocytopenia and also more severe renal damage (a longer anuric phase and a slower recovery of the renal function), thus suggesting a severe multi-target autoimmune aggression. The association of hepatic injury--not explained by prior hepatic disease, B or C hepatitis virus infection or history of alcohol abuse--was encountered in 17% of the cases, without a significant influence on the renal and the general outcome. The outcome of rifampicin-induced ARF is generally favourable, with complete recovery of the renal function within 30 days in 52% of the cases and within 90 days in 92% of the cases. The mortality rate was 3.5%, compared to 21% for the overall ARF population treated during the same period (p < 0.05).