Intestinal cyanosis is caused by the consumption of food containing nitrate, through the intestinal flora will cause the elevation of methemoglobin caused by the appearance of skin, mucous membrane cyanosis and other symptoms. Intestinal cyanosis refers to the consumption of food containing a large amount of nitrate, such as pickles, etc., through the intestinal tract by the intestinal flora of nitrate reduction to nitrite, absorption leads to a reduction in the oxygen-carrying capacity of hemoglobin, followed by the elevation of hemoglobin in the blood of methemoglobin, methemoglobinemia causes intestinal cyanosis, the emergence of the whole body of the skin and mucous membranes is cyanotic purple, abdominal pain, nausea, dizziness, palpitations and other symptoms. The above conditions should be standardized as early as possible under the guidance of a doctor to avoid delaying the condition.