Onions and coffee can be consumed together. It is generally accepted that there is no such thing as food incompatibility, and if you are not allergic to the food, there are no harmful substances that can be produced by consuming the food together. Onions and coffee together do not produce chemical reactions or toxic substances, so they can be consumed together. Onions are relatively rich in nutrients, on average, every 100g of onions mainly contain 9g of carbohydrates, 0.039g of phosphorus, 0.147g of potassium, but also contains calcium, magnesium, vitamin C and so on. The nutritional value of coffee is also relatively high, the average per 100g of coffee mainly contains protein 17.1g, carbohydrates 68.9g, phosphorus 0.204g, magnesium 0.132g. Coffee intake should be moderate, too much can easily lead to insomnia, gastrointestinal discomfort. Therefore, onions and coffee can be consumed together, in moderation, both can add nutrients to the body.