Dyspepsia (from the Greek "δυς-" (Dys-), meaning hard or difficult, and "πέψη" (Pepse), meaning digestion) is chronic or recurrent pain or discomfort centered in the upper abdomen Discomfort, in this context, includes mild pain, upper abdominal fullness and feeling full earlier than expected with eating. It can be accompanied by bloating, belching, nausea or heartburn. Heartburn is excluded from the definition of dyspesia in ICD 10, as it usually has a different cause and management pathway.
Many people get dyspepsia. It is often caused by lifestyle factors, such as smoking and diet, but there are some serious causes such as cancer of the stomach, peptic ulcer disease and some medications. When people have dyspepsia but no risk factors for any of the serious causes, it can be labeled undifferentiated dyspepsia and treated without further investigations. When people have been investigated for dyspepsia but no cause has been found it can be labeled as functional dyspepsia.

Treatment of Functional Dyspepsia and Undifferentiated Dyspepsia