<<Disclaimer: Verify this information before applying it to your situation.>> the other day a member asked about the difference between "xanthan gum and guar gum. also the difference between potato starch and potato starch flour. this explanation was taken from a news letter from "Dietary Specialties" dated autumn 1996 Xanthan gum is a powder milled from the dried cell coat of a microorganism called campestis,grown under laboratory conditions from the fermentation of corn sugar. it is used in foods as a thickener,emulsifier (to improve homogeneity, consistancy, stability or texture), and stabilizer (to impart body,improve consistancy,texture, or "mouth feel"). Guar gum is a powder derived from the seed of the plant Cyamopsis tetragonolobus, a member of the legume family. Guar gum is used as thickener and stabilizer in foods. Guar gum has a high fiber content which used in large amounts may produce a laxitive effect, particularly in those with sensitive digestive systems. using these products is interchangeably is not recomended. Is there a difference between potato starch & potato starch flour? the answer according to the news letter is: potato starch and potato starch flour are the same ingredient. this is a very fine white product with a bland taste. it is used in combination with other gluten-free flours in baking, and can be used alone as a gluten-free thickening agent for cream soups. Please do not confuse potato starch with potato flour. potato flour is a heavy flour with a definite potato taste. when potato flour is an ingredient in a recipe, instant potato flakes may be substituted. as stated above this is from a news letter from a company that deals with foods for celiac people.I do not understand a lot of the terms stated,however if it helps good. alex