People often refer to the entire abdominal region as “the stomach.” Actually, your stomach is an organ located in the upper left part of your abdomen. It’s the first intra-abdominal part of your digestive tract.

Your stomach contains several muscles. It can change shape as you eat or change posture. It also plays an instrumental role in digestion.

When you swallow, food travels down your esophagus, passes the lower esophageal sphincter, and enters your stomach. Your stomach has three jobs:

  1. temporary storage of food and liquids
  2. production of digestive juices
  3. emptying the mixture into your small intestine

How long this process takes depends on the foods you eat and how well your stomach muscles function. Certain foods, like carbohydrates, pass through quickly, while proteins remain longer. Fats take the most time to process.

Reflux occurs when stomach contents such as food, acid, or bile moves back into your esophagus. When this happens twice a week or more, it’s called gastroesophageal reflux disease (GERD). This chronic condition can cause heartburn and irritate your esophagus lining.

Risk factors for GERD include:

Treatment involves over-the-counter remedies and dietary changes. Severe cases require prescription medication or surgery.

Gastritis is an inflammation of your stomach lining. Acute gastritis may come on suddenly. Chronic gastritis happens slowly. According to the Cleveland Clinic, 8 in 1,000 people have acute gastritis and 2 of every 10,000 develop chronic gastritis.

Symptoms of gastritis include:

  • hiccups
  • nausea
  • vomiting
  • indigestion
  • bloating
  • appetite loss
  • black stool due to bleeding in your stomach

Causes include:

  • stress
  • bile reflux from your small intestine
  • excess alcohol consumption
  • chronic vomiting
  • use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs)
  • bacterial or viral infections
  • pernicious anemia
  • autoimmune diseases

Medications can reduce acid and inflammation. You should avoid foods and beverages that cause symptoms.

If the lining of your stomach breaks down you may have a peptic ulcer. Most are located in the first layer of the inner lining. An ulcer that goes all the way through your stomach lining is called a perforation and requires immediate medical attention.

Symptoms include:

  • abdominal pain
  • nausea
  • vomiting
  • inability to drink fluids
  • feeling hungry soon after eating
  • fatigue
  • weight loss
  • black or tarry stool
  • chest pain

Risk factors include:

  • Helicobacter pylori bacteria
  • excessive alcohol consumption
  • overuse of aspirin or NSAIDs
  • tobacco
  • radiation treatments
  • using a breathing machine
  • Zollinger-Ellison syndrome

Treatment depends on the cause. It may involve medications or surgery to stop the bleeding.

Viral gastroenteritis occurs when a virus causes your stomach and intestines to become inflamed. The main symptoms are vomiting and diarrhea. You may also have cramping, headache, and fever.

Most people recover within a few days. Very young children, older adults, and people with other diseases are at increased risk for dehydration.

Viral gastroenteritis is spread through close contact or contaminated food or drink. According to the U.S. Centers for Disease Control and Prevention (CDC), outbreaks are more likely to occur in closed environments such as schools and nursing homes.

The hiatus is the gap in the muscle wall that separates your chest from your abdomen. If your stomach slides up into your chest through this gap, you have a hiatal hernia.

If part of your stomach pushes through and stays in your chest next to your esophagus, it’s called a paraesophageal hernia. This less common type of hernia can cut off your stomach’s blood supply.

Symptoms of hiatal hernia include:

  • bloating
  • belching
  • pain
  • bitter taste in your throat

The cause isn’t always known but can be due to injury or strain.

Your risk factor is higher if you’re:

  • overweight
  • over age 50
  • a smoker

Treatment involves medications to treat pain and heartburn. Severe cases may require surgery. Your doctor may recommend that you:

  • maintain a healthy weight
  • limit fatty and acidic foods
  • elevate the head of your bed

Gastroparesis is a condition in which your stomach takes too long to empty.

Symptoms include:

  • nausea
  • vomiting
  • weight loss
  • bloating
  • heartburn

Causes include:

  • diabetes
  • medications that affect your intestines
  • stomach or vagus nerve surgery
  • anorexia nervosa
  • postviral syndromes
  • muscle, nervous system, or metabolic disorders

Treatment may include medication and dietary changes. In severe cases, surgery may be necessary.

Stomach cancer generally grows slowly over the course of many years. In most cases, it begins in the innermost layer of your stomach lining.

Untreated, stomach cancer can spread to other organs or into your lymph nodes or bloodstream. The earlier stomach cancer is diagnosed and treated, the better the outlook.