A stomach ulcer is an open sore that develops on the lining of the stomach, says the National Health Service. The ulcer occurs when the layer protecting the stomach lining from stomach acid breaks down, damaging the lining.
Signs of a stomach ulcer include:
- Loss of appetite.
- Feeling sick.
- Weight loss.
The agency urges you to seek immediate medical attention if you are vomiting blood, passing sticky, tar-like stools or have worsening, sharp stomach pain.