<<Disclaimer: Verify this information before applying it to your situation.>> Cellulose is a carbohydrate polymer of D-glucose. It is the structural material of plants, such as wood in trees. It contains no gluten protein. Methyl cellulose is a chemically modified form of cellulose that makes a good substitute for gluten in rice-based breads and so forth. I think that methyl cellulose can be purchased from Ener-G foods in Seattle. Don Kasarda, Albany, CA > Sorry if this question has come up before...does anyone know what > cellulose is? Just noticed it on another posting saying it was > "safe." Thank you.