In short, the so-called food additives, that is, the food processing process, in order to maintain or increase the color, flavor and taste of food added additional ingredients. Such as viscosity agents, stabilizers, surfactants, strengthening agents, etc., there are many types and varieties. Food additives related to the development of urticaria are mainly artificial colors, preservatives and antioxidants. Artificial colors are mainly azo and non-azo both. The two commonly used tartaric acid (orange), carmine, sunset red, amaranth red, etc., the latter commonly used brilliant blue, algae red, indigo, etc.. Preservatives commonly used benzoic acid, salicylic acid, ascorbic acid, sulfites, etc. Antioxidants are mainly used in foods containing fat to keep meat fresh and fat not sour, commonly used are butyl hydroxyanisole (BHA), dibutylhydroxytoluene (BHT), vitamin E, propyl gallate (PG), etc.. These food additives are widely used in cold drinks, soft drinks, cakes, cookies, chocolate, margarine, condiments, wine, filling, pickled food, but also widely used in drugs, chewing gum and even in toothpaste. As early as 40 years ago, it was confirmed that the tartaric acid artificial coloring contained in the orange sugar coating of a hormone pill was the cause of chronic urticaria. In order to further confirm the relationship between food additives and the development of chronic urticaria, a series of clinical observations were conducted to verify the relationship. For example, patients with chronic urticaria were restricted to eating rice, fresh vegetables (excluding tomatoes, celery and carrots) and fresh meat, sugar, salt and water for 5 days and observed for recurrence of urticaria. The results showed that 1/3 to 1/2 of the patients with chronic urticaria improved after the restriction and worsened after resuming a normal diet, indicating that food additives are indeed a cause of urticaria. Oral stimulation tests further confirmed that 30% of adults with chronic urticaria reacted positively to one and/or more food additives, with the highest positive reaction rate being for benzoic acid (57%), followed by sodium benzoate (54%), tartaric acid (50%), sunset yellow (27%), amaranth violet (14%), etc. Only individuals reacted positively to non-azo artificial colors. Why do food additives cause urticaria and asthma aggravation? Is it caused by allergic reactions? Observations show that 15% to 20% of urticaria caused by food additives produce the same results when aspirin is given. The nature of the chronic urticarial reaction caused by food additives is the same as the chronic urticarial reaction caused by aspirin, which is an intolerance reaction rather than an allergic reaction. Recently, an extensive epidemiological survey of food additive intolerance was conducted, and although 6.6% to 7.4% of people were found to be intolerant to food additives, only 0.23% to 1% were actually confirmed. Therefore, although food additives can cause intolerance reactions including urticaria, eczema and asthma, they are not as common as expected.