Niacin drugs have certain side effects, but the occurrence of side effects varies from person to person. Common side effects of niacin drugs are skin flushing, itching, etc. In some people, gastrointestinal symptoms such as nausea, vomiting, diarrhea and aggravation of peptic ulcers will occur; in a small proportion of the population, urticaria and hepatic impairment can be seen. Niacin belongs to the B vitamins, also known as vitamin B₃. Niacin drugs in the body is first converted into coenzyme I and coenzyme II, can be used as a coenzyme in the tissue respiration process, catalyzing the important redox reaction, with vasodilatation, lowering blood lipids, reducing cholesterol synthesis, in addition to dissolving fibrin, preventing thrombosis. Niacin analogs are often used in the clinic to prevent and control pellagra and other niacin deficiency diseases, and can also be used to treat hyperlipidemia. Because of its vasodilating effect, it is commonly used in the treatment of vascular migraine, headache, cerebral arterial thrombosis, pulmonary embolism, inner ear vertigo, frostbite, and central retinal choroiditis. Use with caution in patients with glaucoma, diabetes, ulcer disease, and hepatic insufficiency. Niacin drugs have side effects and should be used under the guidance of a medical professional after assessing the individual’s need for medication, and if side effects occur, medical attention should be sought to adjust the treatment plan.