The side effects of niacin generally include skin reactions, central nervous system reactions, and digestive system reactions. Niacin has a vasodilating effect, and its use can lead to the phenomenon of capillary dilatation throughout the body, causing flushing, a feeling of heat, etc., especially on the face and neck. Some patients may experience central nervous system reactions such as dizziness, headache and nervousness. Some patients may also experience gastrointestinal reactions such as abdominal pain, diarrhea, vomiting, regurgitation, bloating, etc., and more serious side effects such as elevated aminotransferases and prolonged prothrombin time may also occur. Diabetes, gout, liver disease, hypotension and other patients should be used with caution, for niacin allergy, arterial bleeding is prohibited. If you need to use niacin, you should use the drug under the guidance of a physician, not on your own, to avoid causing adverse reactions.