Gastroesophageal reflux disease (GERD), or acid reflux, has a number of different causes. The symptoms of acid reflux are caused by the regurgitation of acidic liquid stomach contents back up into the esophagus. Heartburn is the pain characteristically associated with acid reflux and results from irritation of the lining of the esophagus. Some cases of heartburn can produce sharp chest pains in the mid-chest that can be mistaken for the pain of angina. Heartburn is typically worse when an individual lies down after eating and occurs most commonly after mealtimes. Other symptoms that can occur as a result of GERD include nausea, regurgitation (the presence of regurgitated stomach contents in the mouth), and acid-induced erosions of the teeth. The nausea may be severe and lead to vomiting. Certain foods, including peppermint, tomatoes, spicy foods, citrus fruits, alcohol, or caffeinated drinks, may worsen the symptoms. In some cases, acid reflux can cause atypical symptoms, including coughing, otitis media, hoarseness, or wheezing.