Hiccups start at the diaphragm. The diaphragm is a dome-shaped muscle at the bottom of the chest. When we inhale, the diaphragm pulls down to help the air into the lungs. When we exhale, the diaphragm relaxes and air flows out of the lungs. Sometimes, the diaphragm becomes irritated. When this happens, it pulls down in a jerky way, which makes us suck air. When the air rushes in, it hits our voice box; vocal cords close suddenly and we have a big Hiccup. Hiccups can have causes that aren’t due to any underlying disease. Examples include drinking too fast, eating too fast, carbonated beverages, alcohol, smoking or chewing gum.