What are Hiccups? Hiccups are involuntary, repetitive contractions of the diaphragm —the large muscle that separates your chest cavity from your abdomen and plays a vital role in breathing. Each sudden contraction is immediately followed by a rapid closure of your vocal cords, which produces the characteristic "hic" sound. For the vast majority of people, a bout of hiccups is simply a minor annoyance that lasts only a few minutes. Very rarely, they may persist for months, resulting in exhaustion, sleep deprivation, and malnutrition. Symptoms The primary symptom is the involuntary sound itself. However, just prior to the sound, you may also experience: A sudden tightening or spasmodic sensation in your chest, abdomen, or throat. When to See a Doctor While almost all hiccups resolve on their own, you should make an appointment with your doctor if your hiccups last more than 48 hours (clinically defined as ...