Purple cabbage does not have any special effects and functions, but can provide the body with protein, carbohydrates, iodine and other nutrients, contraindications are allergic to the population, hyperthyroidism patients avoid eating. Purple cabbage does not have the efficacy and role of drugs, there is no clear contraindication. However, it has a certain nutritional value, every 100g of purple cabbage (dry) has 1244KJ energy, 26.7g protein, 1.1g fat, 44.1g carbohydrates, as well as carotene, vitamin C and other iodine, phosphorus, potassium, iron, zinc, selenium, copper, manganese and other minerals, which can provide the human body with the nutrients it needs. It should be noted that nori is rich in iodine and should not be consumed by patients with hyperthyroidism. The general population is recommended to eat a moderate amount of seaweed, so as not to overeat and cause abdominal pain, diarrhea and other indigestion symptoms.