Hyperoxaluria occurs in most patients after the conventional jejunoileal bypass
procedure for obesity. The mechanism of hyperoxaluria is complex, involving
persistence of dietary oxalate in solution as well as increased colonic
permeability to oxalate. Endogenous oxalate formation also contributes to
hyperoxaluria. Treatment is unsatisfactory and involves a low-oxalate diet and
simultaneous administration of agents which bind oxalate and bile acids, such as
aluminum hydroxide. Hyperoxaluria was not present in 21 of 22 patients who had
undergone the pancreato-biliary bypass procedure