Habekacin is a new aminoglycoside antibiotic. In this study we want to know the effect of increasing dose of habekacin on renal function and on renal morphology. We decide to compare the renal alterations induced by habekacin to these provoked by gentamicin, netilmicin and amikacin. Female Wistar rats received intraperitonally a single injection daily of 10, 30, 50, 150 mg/kg of habekacin for seven days. Wistar rats received also 50 mg/kg gentamicin, 50 mg/kg netilmicin and 150 mg/kg amikacin. No mortality was observed in groups treated with 10, 30, 50 mg/kg habekacin but 50 per cent of rats died with 150 mg/kg habekacin. Habekacin--30 mg/kg seven days--induced a decrease of cortical enzymatic activities, an increase of the number of lysosomes, a great accumulation of myeloid bodies, an alteration of lysosomal membranes Habekacin--50 mg/kg seven days and 150 mg/kg--induced a decrease of creatinine clearance and ultrastructural alterations of renal tubular cells. Comparative studies with other aminoglycosides showed that amikacin--150 mg/kg was the lesser nephrotoxic drug. With a same dose of 50 mg/kg, gentamicin appeared lesser nephrotoxic than habekacin and habekacin seemed to induce a same degree of renal modifications than netilmicin. With the dose of 150 mg/kg habekacin this drug was higher nephrotoxic than 50 mg/kg gentamicin. In conclusion, if it could be necessary to use habekacin and to prefer this aminoglycoside to gentamicin from an antibacterial activity point of view it is necessary to keep in mind that this drug is potentially nephrotoxic and that the dosage had to be strictly respected.(ABSTRACT TRUNCATED AT 250 WORDS)