What a hiatal hernia is
The diaphragm is the large, thin muscle that separates the chest from the abdomen. It has a small opening, the hiatus, through which the esophagus, the tube that carries food from the mouth, passes before joining the stomach. Mayo Clinic explains that in a hiatal hernia, the upper part of the stomach pushes up through that opening and into the chest.
MedlinePlus notes that the diaphragm normally helps keep stomach acid from coming up into the esophagus. When there is a hiatal hernia, it is easier for acid to come up, which is why the condition is often discussed together with reflux.
Why some hernias cause no symptoms
Mayo Clinic says that most small hiatal hernias cause no symptoms. Many people never know they have one unless it is found during tests for another condition. MedlinePlus explains that people usually find out when they are being tested for reflux, heartburn, chest pain or abdominal pain.
Finding a small hernia by chance does not necessarily mean it explains other symptoms, and MedlinePlus states that no treatment is needed if a hiatal hernia does not cause symptoms or problems.
Reflux and other possible symptoms
Larger hiatal hernias can allow food and acid to back up into the esophagus. Mayo Clinic lists possible symptoms:
- heartburn and acid reflux
- regurgitation, the backward flow of swallowed food or liquid into the mouth
- trouble swallowing
- chest or abdominal pain
- feeling full soon after eating
- shortness of breath
MedlinePlus adds that the resulting reflux (gastroesophageal reflux disease, or GERD) can cause a dry cough, bad breath, nausea or vomiting, breathing problems and wearing away of the teeth. Reflux has other causes too: not everyone with reflux has a hiatal hernia, and not every hiatal hernia causes reflux. Our guide on GERD cough covers one of these effects.
Possible causes and risk factors
The cause is often unclear. Mayo Clinic and MedlinePlus describe weakened muscle tissue that lets the stomach bulge up through the diaphragm, possibly related to:
- age-related changes in the diaphragm
- injury to the area, for example after trauma or certain types of surgery
- being born with a very large hiatus
- constant, intense pressure on the surrounding muscles, as with coughing, vomiting, straining during bowel movements, exercising or lifting heavy objects
Hiatal hernias are most common in people aged 50 or older and in people with obesity, and MedlinePlus adds smoking as a risk factor.
Chest pain and other warning symptoms
Mayo Clinic notes that vomiting blood or passing black stools could mean bleeding in the digestive tract, which needs urgent medical care. Persistent trouble swallowing, repeated vomiting or shortness of breath also need prompt assessment.
Chest pain has many possible causes, including heart problems. Even if you know you have a hiatal hernia, new, severe or unusual chest pain should be assessed urgently rather than assumed to be reflux. For other lasting symptoms that worry you, Mayo Clinic advises making an appointment with a healthcare professional.
How clinicians investigate
MedlinePlus lists the tests that commonly find a hiatal hernia:
- a chest X-ray
- an X-ray with a barium swallow, in which you drink a liquid that shows the outline of the esophagus and stomach
- an upper endoscopy, in which a thin tube with a camera is passed down the throat to look at the esophagus and stomach
Which test is used, if any, depends on the symptoms and on what the doctor needs to rule out. Many hernias are found when these tests are done for reflux, heartburn or pain.
Observation, reflux symptoms and food tolerance
If a hiatal hernia causes no symptoms or problems, MedlinePlus says no treatment is needed. When there are reflux symptoms, Mayo Clinic says self-care measures or medicines can usually relieve them. The lifestyle changes listed by MedlinePlus include:
- eating smaller meals
- avoiding foods that trigger your symptoms
- not smoking
- not drinking alcohol
- losing weight, when advised
There is no single list of forbidden foods that applies to everyone: the aim is to identify which foods and meal sizes you tolerate. These measures relieve reflux; they do not move the stomach back into place or repair the hernia. Our guide on foods to avoid with acid reflux gives more detail.
A doctor may also recommend antacids or other medicines to reduce acid. Which medicine, the dose and how long to take it are decided with the prescriber. For adults with a diagnosed hiatal hernia and reflux, our nutrition practice in Bilbao offers dietary support coordinated with your doctor; we do not diagnose or treat the hernia itself (consultations are in Spanish).
When surgery may be considered, and a consultation record
MedlinePlus explains that surgery may be needed if lifestyle changes and medicines do not help. Mayo Clinic notes that a very large hiatal hernia might need surgery. Most people with a hiatal hernia do not need an operation, and the decision depends on symptoms, complications and the doctor’s assessment rather than on the presence of a hernia alone.
If surgery is suggested, it is reasonable to ask why it is recommended in your case, what alternatives exist, what the expected benefits and risks are, what recovery involves and what eating will be like afterwards.
Before any appointment, a short record helps:
- your symptoms, how often they happen and what triggers them, including meal size, timing and specific foods
- treatments you have tried, how long and how well they worked
- any warning signs, such as trouble swallowing, vomiting or black stools
- weight changes, smoking and alcohol
- questions about tests, medicines or surgery
Where the sources differ
The two sources agree on the basics but frame the condition differently. MedlinePlus links hiatal hernia closely with GERD and lists reflux-related symptoms, while Mayo Clinic adds symptoms that are not only reflux, such as early fullness, shortness of breath and signs of bleeding. MedlinePlus includes smoking as a risk factor, which the Mayo Clinic page does not mention.
On surgery, Mayo Clinic refers to very large hernias and MedlinePlus to cases where lifestyle changes and medicines do not help. Neither page details the types of operation or their results. The Mayo Clinic page is dated July 2025 and the MedlinePlus summary, based on information from the National Institute of Diabetes and Digestive and Kidney Diseases, was updated in November 2025.
In summary
A hiatal hernia is when the upper part of the stomach bulges through the diaphragm into the chest. Small hernias are common, especially after 50, and often cause no symptoms or need for treatment. Larger ones can cause heartburn, regurgitation, trouble swallowing, chest or abdominal pain or early fullness.
Vomiting blood, black stools, new or severe chest pain or inability to swallow need urgent care. Reflux symptoms usually improve with smaller meals, avoiding trigger foods, not smoking or drinking alcohol, losing weight when advised and medicines; these measures relieve symptoms but do not repair the hernia. Surgery is considered for very large hernias or when other treatments do not help.
Frequently asked questions about hiatal hernia
These answers are general information and do not replace an examination or individual medical advice.
Can a hiatal hernia cause no symptoms?
Yes. Most small hiatal hernias cause no symptoms and are found by chance during tests for other problems. If there are no symptoms or problems, no treatment is needed.
Is every case of reflux caused by a hernia?
No. A hiatal hernia makes it easier for acid to come up, but reflux has other causes, and many hernias cause no reflux at all.
Can food changes repair the hernia?
No. Smaller meals and avoiding trigger foods can relieve reflux symptoms, but they do not move the stomach back into place.
Does every hernia need surgery?
No. Surgery may be considered when a hernia is very large or when lifestyle changes and medicines do not control symptoms.
What symptoms should not be assumed to be reflux?
New or severe chest pain, vomiting blood, black stools, inability to swallow and shortness of breath. These need prompt medical assessment.
What should I ask before considering an operation?
Why it is recommended for you, what the alternatives are, the expected benefits and risks, what recovery involves and how eating will change afterwards.
Sources
This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.