Neutrophil superoxide formation was similar when cells were incubated in self-made, non-autoclaved pH 7.4, lactate-based peritoneal dialysis solutions or in their self-made, non-autoclaved, pH 7.4, bicarbonate-based counterparts. On the other hand, commercially available, autoclaved, pH 7.4, lactate-based peritoneal dialysis solutions resulted in inhibition of superoxide production when compared to their self-made, non-autoclaved, pH 7.4, lactate-based or bicarbonate-based counterparts. The cause for this inhibition of superoxide generation is at present unknown.