Purple potato skin does not contain harmful substances, it is appropriate to eat. Purple potato skin is the outer skin of purple potatoes, every 100 grams of purple potatoes contain 119.3 calories, 17.6 grams of carbohydrate compounds, 1.17 grams of dietary fiber, 2.34 grams of protein, 97mg of potassium, 121mg of phosphorus, 23mg of calcium, 1.36mg of manganese, 1.45mg of zinc, 1.1mg of iron, 0.19mg of copper. Eating purple potato skin can supplement these substances for the human body, usually can be appropriate to eat. Purple potato skin inside the dietary fiber than other parts of the more, constipation patients can be appropriate to eat more. At the same time combined with other foods to increase the diversity of nutrition. Diabetic patients need to reduce the intake of other staple foods after the intake of purple potatoes.