There is a risk of a loop of bowel getting stuck in the hernia resulting in either obstruction to flow of bowel contents or strangulation where the blood supply to the bowel itself is compromised and the bowel effectively dies.

So most hernias should be repaired with an operation. This can be with a traditional open operation or with a laparoscopic (key-hole) approach using a mesh and usually performed as a day procedure.

The laparoscopic method has the advantage of causing less post operative pain and patients are able to return to full activity in a shorter time. 
See what the National Institute for Health and Clinical Excellence has to say about inguinal hernia repair.