1, onion should not be eaten in excess, it will flatulence and fart, causing unhappiness.

2. People suffering from eye diseases such as glaucoma and cataract should not eat it.

3. People suffering from digestive system diseases and prone to gas accumulation in the stomach are not suitable for eating.

4, people with itchy skin should not eat onions, or aggravate the condition.

5, improper preservation of cold onion, will lead to a large number of bacteria reproduction, easy to cause diarrhea, abdominal pain and other symptoms after eating, generally speaking, it can not be eaten at room temperature for more than 4 hours.