<prompt> Which of the following laxatives lowers blood ammonia level in hepatic encephalopathy?BisacodylLiquid paraffinLactuloseMagnesium sulfate  <response>: Ref: KDT 6e p655 Lactulose is degraded to lactic acid that conves NH3 to NH4. As ionic molecules cannot cross biological membranes, it is not absorbed and is thus excreted. 