Vitamin B3 is also known as niacin or nicotinic acid. Vitamin B3 is a type of water-soluble vitamins. It helps to lower the bad cholesterol levels in the body, boost the good cholesterol levels, reduces the risks of atherosclerosis and heart diseases. However, taking too much vitamin B3 can lead to certain side effects and the common one is flushing. Flushing is described as the feeling of warmth and redness of the skin commonly in the face, neck and upper chest. This occurs when the small blood vessels under the skin are dilated leading to gushing of blood into blood vessels. Flushing occurs about 30 minutes after the intake of large doses of vitamin B3 or nicotinic acid and usually gets better within an hour. Other symptoms that are associated with flushing are burning sensation, itchiness, low blood pressure, headache, and dizziness. Hence, vitamin B3 or nicotinic acid should only be taken according to the prescribed doses.