Ingredient database › Prebiotics (FOS)
Is Prebiotics (FOS) good or bad in dog food?
Prebiotics (FOS) is a nutritional supplement and rates as Good in our analysis.
Good Bottom line: Prebiotics (FOS) is a good, beneficial ingredient — a positive sign wherever it appears on the label.
Feeds healthy gut bacteria.
This is a solid, beneficial ingredient and a positive sign wherever it appears on the label.
Built on AAFCO & FDA pet-food criteria · Last updated June 2026 · How we rate
What is Prebiotics (FOS)?
Prebiotics (FOS) is a nutritional supplement used in dog food. On a label it may also appear as: fructooligosaccharides, fos, chicory root, inulin.
What to look for on the label
Ingredients are listed by weight, so the ones near the top make up most of the recipe. Prebiotics (FOS) near the top is a good sign. The fastest way to judge a whole product is to paste its full ingredient list into our free dog food checker, which grades it A–F and flags every ingredient like this one.
How Prebiotics (FOS) affects the WoofScore
Our grade rewards named whole proteins, vegetables, fruit and beneficial supplements, and penalises vague by-products, cheap fillers, artificial colours and controversial preservatives. Prebiotics (FOS) contributes as a good-tier item; read the full scoring methodology to see exactly how the grade is calculated.