E104, also known as quinoline yellow, is a synthetic food dye commonly used in various food products. It is primarily used to impart a yellow color to items such as candies, beverages, and baked goods. E104 is classified as a color additive and is regulated by food safety authorities in many countries. The use of E104 is subject to specific guidelines, as some individuals may experience allergic reactions or sensitivities to synthetic dyes. It is important for consumers to check product labels for E104 and other additives, especially if they have known allergies or dietary restrictions.