Hospital acquired acute kidney injury is an important negative outcome predictor for hospitalized patients. Uremic toxins accumulated after a given renal insult. Some of these uremic toxins are protein bound and may accumulated after renal impairment, owing to both impaired filtration, and inflammation. Recent animal studies have reported that accumulation of uremic toxins, namely indoxyl sulfate and p-cresol, would down regulate endothelial progenitor cells and in turn affect renal recovery. Elimination of these protein bound uremic toxins with an activated charcoal would help restore endothelial function. We will conduct a double blinded randomized placebo controlled trial, which aims to determine that if oral activated charcoal will retard progression of AKI. Also, a panel of markers for endothelial function will also be determined.