Onions are warm and pungent and contain many nutrients such as vitamins, fiber, prostaglandin compounds and polysaccharides, which are beneficial to the human body when consumed in moderation. However, onion is a spicy food, some people are not suitable for consumption, the following three groups of people: 1, allergic people: some allergic people will contact with onion juice rash, hives and other performance, should be avoided; 2, gastrointestinal disease patients: such as gastritis, gastric ulcer, duodenal ulcer, etc., because the gastrointestinal protective barrier is damaged to varying degrees, the general level of gastric acid is high, the consumption of onion may be on the gastrointestinal The consumption of onions may stimulate the gastrointestinal mucosa, thus aggravating the gastrointestinal discomfort and even leading to abdominal pain and diarrhea; 3. Patients taking medication or post-operative patients: usually spicy food should be avoided during medication and perioperative period, especially after gastrointestinal surgery, the consumption of onions may cause abdominal distension and abdominal pain, which is not conducive to the recovery of the patient’s body. In addition, patients with eye diseases should be cautious about eating onions, especially raw onions, as the pungent gas and juice emitted can cause irritation to the eyes. Patients with dermatitis are also not suitable for eating onions, which may lead to aggravation of itchy skin symptoms. From the perspective of Chinese medicine, patients with heat illnesses and yin deficiency are also not suitable to eat spicy and stimulating foods and should be aware of this.