Onions contain a substance that could help people with acne. But they have to be willing to take their onions raw.
Antioxidants in onions may help reduce inflammations that are implicated in acne. The sulfur-containing essential oils in onion stimulate production of the molecule glutathione. A study found glutathione levels to be lower in people who were prone to skin breakouts. The antioxidant is most potent when the onions are eaten raw or lightly cooked.