Are the Green Parts of Green Onions Low FODMAP? A Guide for a Gut-Friendly Diet

November 7, 2025 •

4 min read

For individuals with Irritable Bowel Syndrome (IBS), navigating a low FODMAP diet can be tricky, as many flavorful ingredients are off-limits. A common question that arises for those looking to add flavor without triggering symptoms is, are the green parts of green onions low FODMAP and safe to eat?

Quick Summary

The green leafy tops of green onions are low in FODMAPs and safe for most individuals on a low FODMAP diet. The white bulb, however, contains high levels of fructans and should be avoided to prevent digestive distress.

Key Points

Green Tops Only: The green, leafy parts of green onions are low in FODMAPs and safe for most individuals on a low FODMAP diet.
Avoid the Bulb: The white bulb and pale green section of the green onion are high in fructans and should be avoided.
Portion Control is Key: While the green tops are safe, moderation is still important. Monash University recommends a serving of up to 75g (1.5 cups).
Versatile Flavor: Use the chopped green tops as a garnish, sauté them in oil, or add them to soups and stir-fries to add a mild onion flavor.
Fructans are Water-Soluble: The FODMAPs in onions are water-soluble, meaning they won't infuse into oil, allowing for low FODMAP onion-infused oils.
Alternative Alliums: Other low FODMAP allium options include chives and the green leaves of leeks, offering variety in your cooking.

Understanding FODMAPs and Alliums

FODMAPs, which stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols, are short-chain carbohydrates that can be poorly absorbed in the small intestine. For individuals with IBS, this poor absorption can lead to fermentation by gut bacteria in the large intestine, causing uncomfortable symptoms like bloating, gas, and abdominal pain. Onions, including green onions, are known to contain fructans, a type of oligosaccharide. However, not all parts of the green onion are equally high in these fermentable carbs.

The Allium Family: A High and Low FODMAP Divide

Standard brown, red, and white onions are high in fructans and typically restricted during the elimination phase of the low FODMAP diet. The key lies in understanding that the FODMAP content is concentrated in specific parts of the plant. In the case of green onions, a clear divide exists between the bulb and the green leaves. This is because fructans are water-soluble and become more concentrated in the plant's bulb, while the green, leafy tops are significantly lower in these compounds. This distinction is crucial for anyone trying to add an onion-like flavor to their meals without triggering IBS symptoms.

Are the Green Parts of Green Onions Low FODMAP?

Yes, the green tops of green onions (or scallions) are low in FODMAPs and a safe choice for those on a low FODMAP diet. According to testing by Monash University, which sets the standard for FODMAP content, a generous serving of up to 75g (or 1 ½ cups) of the green tops is considered low FODMAP. This makes them a fantastic ingredient for adding a fresh, mild onion flavor to your cooking. In contrast, the white bulb and the pale green section where the bulb begins are high in fructans and should be avoided during the elimination phase of the diet.

Practical Ways to Use Green Onion Greens

Flavor Base: Sautéing the chopped green tops in a low FODMAP oil, like garlic-infused olive oil, can create a delicious and safe flavor base for soups, curries, and stir-fries.
Garnish: Sprinkling finely chopped green onion tops over finished dishes adds a fresh, zesty flavor and a pop of color. This works well for salads, tacos, eggs, or mashed potatoes.
Freezing: To avoid waste, you can chop and freeze leftover green onion tops. They can be used directly from frozen in cooked dishes.
Regrowing: For a constant supply, place the white root ends in a jar with an inch of water on a sunny windowsill. Change the water every couple of days, and the green tops will regrow.

Low FODMAP Flavor Alternatives: Green Onion Greens and More

Green onion greens are a great starting point, but other safe options can provide similar flavor profiles. The following table compares green onion parts with other common low FODMAP allium alternatives:


Feature	Green Onion Greens	Green Onion Whites/Bulb	Leek Greens	Chives	Onion-Infused Oil
FODMAP Status	Low FODMAP	High FODMAP	Low FODMAP	Low FODMAP	Low FODMAP
Recommended Portion	75g or 1.5 cups	Avoid (High Fructans)	75g or 1 cup	4g (sprinkle)	As desired
Flavor Profile	Mild onion flavor	Strong, pungent onion	Mild, earthy onion	Mild, delicate onion	Garlic/onion flavor
Best For...	Garnishes, stir-fries, soups	Flavor base (outside low FODMAP)	Sautéing, soups, stews	Garnishes, dressings	All-purpose flavor base
Key Consideration	Fructans are water-soluble	Fructans concentrated in bulb	Safe portion size matters	No detectable FODMAPs	Flavor without fructans

Reading Labels and Sourcing Flavor

When buying green onions, select bunches with firm, vibrant green tops. It’s important to remember that terminology can vary (scallions, spring onions), but the rule remains the same: use the dark green parts and discard the white and pale green bulbs during the elimination phase. While garlic and onion are pervasive in processed foods, fructans are not oil-soluble. This is why garlic- or onion-infused oil is an excellent way to impart flavor. When using infused oils, ensure they are made by infusing whole garlic or onion pieces in oil and then straining them out. This prevents the water-soluble fructans from contaminating the oil.

Conclusion

For those managing IBS on a low FODMAP diet, the answer to "Are the green parts of green onions low FODMAP?" is a definitive yes, with a crucial caveat: only the green, leafy tops are safe in designated portion sizes. By being mindful of this, and by utilizing other low FODMAP allium alternatives like leek greens, chives, and infused oils, you can reclaim the classic flavor of onions in your cooking without sacrificing your digestive comfort. Experimenting with these ingredients can open up a world of flavorful possibilities, proving that a low FODMAP diet doesn't have to mean a bland one. The key is knowing which part of the plant to use and in what quantities, informed by resources like the Monash University app and reputable guides from FODMAP experts.

For further low FODMAP guidance, refer to the Monash University Low FODMAP Diet.

Frequently Asked Questions

No, you should only use the green, leafy tops during the elimination phase of a low FODMAP diet. The white bulb contains high levels of fructans, which are a type of FODMAP and can trigger digestive symptoms.

According to Monash University, a safe low FODMAP serving size for the green tops of green onions is up to 75g, or about 1 ½ cups, per meal.

The FODMAPs in green onions, known as fructans, are water-soluble carbohydrates that are more highly concentrated in the plant's bulb (the white part). The green leaves contain a much lower concentration, making them low FODMAP.

You can use the green tops of green onions, the green leaves of leeks, or chives. Another effective method is to use garlic- or onion-infused oil, as the fructans are not oil-soluble.

Yes, you can chop and freeze leftover green onion greens. They are best used in cooked dishes like soups, sauces, or stir-fries rather than raw, as the freezing process can affect their texture.

To regrow green onions, place the white root ends in a glass with a small amount of water. Keep the roots submerged in a sunny spot, changing the water every couple of days. The green tops will regrow, providing a constant supply.

Besides green onion greens, chives are also considered low FODMAP. For other onion-like flavors, leek greens are low FODMAP in specific portions. It's always best to check the Monash University app for the latest portion size guidance.