Is red onion low FODMAP?

High FODMAP, usually limited

Red onion is high FODMAP and is usually limited during the elimination phase.

High FODMAP

Fructan

Last reviewed October 24, 2026

Red onion on a low FODMAP diet

Leave red onion out during the elimination phase, which usually lasts two to six weeks.
Use one of the lower-FODMAP swaps below instead.
High FODMAP doesn't mean forever: during reintroduction, many people find they tolerate some high FODMAP foods in smaller amounts.

Which FODMAPs are in red onion

Fructan: Fructans are chains of fructose found in wheat, garlic, onion and some vegetables. People can't fully digest them, so they reach the large intestine, where gut bacteria ferment them. Read more about high FODMAP foods to avoid with IBS.

Lower-FODMAP swaps

More vegetables

rhubarb

Low FODMAP

scallion bulbs (white part)

Common questions

Is red onion low FODMAP?

Red onion is high FODMAP and is usually limited during the elimination phase. It contains fructans.

Which FODMAPs are in red onion?

Red onion contains fructans. Fructans are chains of fructose found in wheat, garlic, onion and some vegetables. People can't fully digest them, so they reach the large intestine, where gut bacteria ferment them.

Can I have red onion during the low FODMAP elimination phase?

It's usually best left out during elimination and tested later, during reintroduction.

What can I use instead of red onion?

Lower-FODMAP options include scallion greens, chives and leek leaves.

How do I test red onion during reintroduction?

Red onion belongs with the fructans group, which is often tested with regular bread or pasta. Test one group at a time, starting small and increasing over a few days, and note how you feel.

Learn more

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