1, water chestnut and raw fish, clams. Raw fish and clams contain sulfatase, which will destroy the B vitamins in water chestnut and reduce the nutritional value of food.

2, patients with spleen and stomach deficiency and cold should not eat: water chestnut is cold, so patients with spleen and stomach deficiency and blood deficiency should not eat, otherwise it will aggravate the condition.

3, patients with fatigue cough should not eat: patients with fatigue cough should warm the middle and tonify the deficiency, strengthen the spleen and nourish the lungs, enhance the digestive function, facilitate the absorption of nutrients, and enhance the body's disease resistance, then chronic lung and tracheal diseases will gradually be alleviated. Water chestnut is suitable for patients with cough due to lung heat, expectoration with yellow phlegm and early tracheal diseases, but not for patients with cough due to fatigue.

4, patients with low blood pressure should not eat: water chestnut has a certain antihypertensive effect, so patients with low blood pressure should not eat.

5, diabetic patients should not eat: water chestnut is rich in sugar, which will increase blood sugar after eating and aggravate the condition of diabetic patients.