Only 2% of people worry most about digestive diseases compared with other illnesses, even though they account for one in eight deaths, research suggests.
The Digestive Disorders Foundation found such conditions came second from last when nearly 1,000 adults were asked which conditions concerned them.
Digestive disorders include diseases such as colon cancer and liver disease.
As part of National Gut Week, people are being encouraged to eat healthily and not ignore symptoms.
'Early detection key'
The Digestive Disorders Foundation (DDF) accepts some people do feel embarrassed about talking about "bodily functions", but says a doctor will not be and will soon be able to put a patient at ease.
It said over a third of the population regularly suffer from digestive illnesses such as irritable bowel syndrome, constipation, diarrhoea, stomach-aches, nausea and sickness.
One in eight admissions to general hospitals in the UK are for gut conditions and diseases, and almost one in four main operations within general hospitals are performed on the digestive tract.
Alison Hesketh, director of the DDF, said: "Diseases and conditions of the digestive tract are one of the nation's biggest causes of death.
"Yet, because of taboos, ignorance and embarrassment, many people are left isolated and suffering in silence from illnesses that could be treated."
Dr Nick Read, Medical Adviser of the IBS (Irritable Bowel Syndrome) Network, added: "Don't be afraid to discuss your gut is our key message. Go to see your doctor if you think that you have a digestive problem.
"Early detection will normally mean a cure. For example, if bowel cancer is detected early enough, it is usually treatable."
Fiona MacCrae, who suffered irritable bowel syndrome for 13 years from the age of 11, said it was important people who had symptoms sought medical advice.
"For a long time, I was told it was 'just me and my stomach'.
"Then I finally found a doctor who was prepared to listen and carry out tests. When she said I had IBS it was quite a relief.
"I have been able to do something about it, change my diet."
She added: "If anyone has symptoms which are upsetting their life, they should go to the doctor and keep pressing to get something done."
During Gut Week, people with concerns about their digestive health can contact a specialist nurse for advice by calling 0208 743 4287 from 6pm to 10pm every evening from Monday 19th July until Friday 1st August.