Toxin A produced by Clostridium difficile, the causative agent of pseudomembranous colitis and antibiotic-associated diarrhea, was shown to bind to synthetic oligosaccharide sequences attached to an inert support (SYNSORB). The oligosaccharide sequences that bind to toxin A were related to sequences previously identified as potential receptors for the toxin. Various SYNSORBs containing a variety of oligosaccharides were examined for their potential to neutralize toxin A activity from toxin-containing solutions as well as clinical stool samples from patients with either pseudomembranous colitis or antibiotic-associated diarrhea. The results from neutralization experiments suggest SYNSORB can effectively neutralize toxin A activity from stool samples and thus could serve as a potential therapy for C. difficile-associated diarrhea.