The potato part
A plain fry is a cut potato fried in vegetable oil, often with a little dextrose and salt. Nothing in that recipe needs an animal. The answer changes in two places: the fat in the fryer, and anything added to the oil or the fries.
McDonald’s: one name, two recipes
McDonald’s US fries are not vegan. As of 7 November 2026, the ingredient list on the US product page puts a beef flavour inside the vegetable oil:
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Potatoes, Vegetable Oil (canola Oil, Corn Oil, Soybean Oil, Hydrogenated Soybean Oil, Natural Beef Flavor
The flavour carries a bracket naming wheat and milk derivatives, and a footnote under the list spells it out:
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natural Beef Flavor Contains Hydrolyzed Wheat And Hydrolyzed Milk As Starting Ingredients.
The page’s allergen line names wheat and milk. Milk alone rules the fries out, whatever the flavour owes to beef.
The UK recipe is different. As of 7 November 2026, the UK product page lists potatoes, a sunflower and rapeseed oil blend, and dextrose, and adds:
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Prepared in the restaurants using a non-hydrogenated vegetable oil. Salt is added after cooking.
McDonald’s UK also answers the vegan question directly, in a help page dated May 2018 and still online:
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Once at the restaurant, our fries are simply cooked in dedicated frying vats in a non-hydrogenated blend of sunflower and rapeseed oil which is 100 percent suitable for vegans.
The same brand can sell a vegan fry in one country and a fry with milk in another, so check the page for the country you are in.
The frying fat
Away from the chains, the fryer is the first thing to check. The Vegetarian Society’s hidden-ingredients guide (2026) says this about chips:
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Chips beef dripping or animal fat may be used by restaurants or chip shops for cooking chips.
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Dripping is the British term for beef fat that has been rendered
Fries cooked in dripping are not vegan, whatever the potato is. Our tallow page covers rendered animal fat in more detail.
The seasoning and flavouring
Seasoned and flavoured fries add another list to read. US rules define natural flavour by the materials it may come from, and the list includes animal ones:
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meat, seafood, poultry, eggs, dairy products, or fermentation products thereof
A menu line that says only natural flavour cannot settle the question on its own. Our natural flavours page covers how that category works.
Asking in a restaurant
The Vegetarian Society’s guide covers the practical side:
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Proprietors do not have to say whether cooking methods are veggie friendly, so it is always worth asking.
Ask what the fries are cooked in, and whether that oil also fries battered or meat items. Then ask whether anything is added to the oil or the fries, since the McDonald’s US flavour sits in the oil itself. If the answer is vague, choose something you can check.