<human>:  What is the difference between gastritis and GERD?
<bot>: The primary difference between gastritis and GERD is the cause. Gastritis is usually caused by an infection or irritation of the stomach lining, while GERD is caused by reflux of stomach acid into the lower esophagus. Gastritis tends to cause mild discomfort and indigestion, whereas GERD causes more intense symptoms such as heartburn, chest pain, and difficulty swallowing.