Nutri Marshmallow & Gamma Oryzanol. Nutri Marshmallow & Gamma Oryzanol is a powerful digestive formula which combines the mucilagenous herbs Marshmallow Root and Slippery Elm Bark with Gamma Oryzanol and plant enzymes for a soothing effect on the gastrointestinal tract. This formula is well tolerated by those with a sensitive digestive tract.