R12: Heartburn

You have heartburn.

You have pain, most of which starts in the left upper abdomen. This pain can also spread to the chest and throat. Occasionally you also have to do sour burps. These symptoms are often caused by an inflamed oesophagus (gullet).

The cause is often that the sphincter muscle connecting the oesophagus and the stomach does not close all the way, causing stomach acid to leak from the stomach back into the oesophagus. The gastric acid attacks the mucous membrane of the gullet. As a result, the oesophagus can become inflamed. There are other causes of heartburn as well. The oesophagus can become inflamed due to pathogens, for example.

When the oesophagus is inflamed, some people feel it as heartburn. The symptoms can intensify when lying down or with physical exertion.

Additional indicator

On medical documents, the ICD code is often appended by letters that indicate the diagnostic certainty or the affected side of the body.

  • G: Confirmed diagnosis
  • V: Tentative diagnosis
  • Z: Condition after
  • A: Excluded diagnosis
  • L: Left
  • R: Right
  • B: Both sides

Further information


This information is not intended for self-diagnosis and does not replace professional medical advice from a doctor. If you find an ICD code on a personal medical document, please also note the additional indicator used for diagnostic confidence.
Your doctor will assist you with any health-related questions and explain the ICD diagnosis code to you in a direct consultation if necessary.


Provided by the non-profit organization “Was hab’ ich?” gemeinnützige GmbH on behalf of the Federal Ministry of Health (BMG).