We performed a crossover study to compare the effect of vitamin E-modified dialyzers on acute intra-dialytic symptoms, with other membranes. Twenty patients on hemodialysis were studied. They were divided into two equal groups of low-flux (C15NL, E15NL) and high-flux (F60, EE15NL) membrane dialyzers. Within each group, a vitamin E-modified dialyzer was compared with another dialyzer in a crossover design over a two-month period. All study patients were seen during each dialysis session by a physician and the occurrence of intra-dialytic symptoms were recorded. There was a significant overall improvement in the incidence of acute intra-dialytic symptoms with the use of vitamin E-modified dialyzers as compared with the other membranes. This effect was more for cuprophane than polysulfone. The occurrence of hypotensive episodes did not differ. Our study indicates that we can achieve a reduction in the incidence of acute intra-dialytic symptoms with the use of vitamin E-modified membrane as compared to cuprophane and polysulfone.