ABSTRACT
Primary sclerosing cholangitis (PSC), a rare progressive liver disease characterized by cholestasis and bile duct fibrosis, has no accepted, effective therapy known to delay or arrest its progression. We report a 15 year old female patient diagnosed with PSC and moderate chronic active ulcerative colitis (UC) who achieved normalization of her liver enzymes and bile ducts, and resolution of her UC symptoms with colonic mucosal healing, after treatment with a single drug therapy of the antibiotic oral vancomycin. We postulate that the oral vancomycin may be acting both as an antibiotic by altering the intestinal microbiome and as an immunomodulator. Oral vancomycin may be a promising treatment for PSC that needs to be further studied in randomized trials.