Hiccups are equal parts annoying and mysterious. They often seem to show up out of nowhere and stick around for as long as they please — but why? And what's causing them?
Hiccups are really just involuntary contractions of your diaphragm muscle, caused by an irritation of the nerves in your chest and neck. They tend to happen after a large meal, drinking alcohol or carbonated beverages, or sudden bout of excitement, but they can also come out of nowhere. When the diaphragm spasms, it causes you to suck in a breath, while your vocal cords close off a fraction of a second later, providing that excellent "hic" sound.
Nearly all mammals experience hiccups. They've been observed in rabbits, dogs, cats, and horses, as well as humans. And they happen throughout our lives: It is not uncommon for pregnant moms to feel the rhythmic bouncing of babies' hiccups before they're even born. Some scientists have proposed that this suggests hiccups must serve an important purpose, but no one is sure what that could be. Theories include that the hiccup reflex might help protect you from choking or that it's the body's way of helping you burp — but there's no proof either way.
For most people, hiccups will continue for a few minutes and be gone within 48 hours. But sometimes, prolonged episodes can signal a true medical issue. According to the Mayo Clinic, that's most often a nerve condition related to things like gastroesophageal reflux or other problems in your neck or ear. For protracted episodes of hiccups, solving the underlying health issue or taking certain medications can help.
But for shorter episodes that are unrelated to a medical issue, it's unclear how to stop them, aside from waiting it out. There are an infinite number of supposed hiccup "cures," but none of them really have any scientific evidence behind them. That said, drinking water, swallowing a bunch, eating a spoonful of peanut butter, or sticking out or biting your tongue may help keep you busy while you wait for things to settle down.