A hiccup is an involuntary contraction of the diaphragm, the muscle that separates the chest from the abdomen. This contraction is followed by a sudden closure of the vocal cords, which produces the characteristic "hic" sound. Hiccups can occur for various reasons, including eating too quickly, consuming carbonated beverages, or experiencing sudden changes in temperature. Most hiccups are harmless and resolve on their own within a few minutes. However, persistent hiccups lasting more than 48 hours may indicate an underlying medical condition and should be evaluated by a healthcare professional. Common remedies include holding one's breath or drinking water.