People are usually advised to avoid foods that bother them.Gastritis is believed to affect about half of people worldwide. In 2013 there were approximately 90 million new cases of the condition. As people get older the disease becomes more common. It, along with a similar condition in the first part of the intestines known as duodenitis, resulted in 50,000 deaths in 2015. H. pylori was first discovered in 1981 by Barry Marshall and Robin Warren. Signs and symptoms
Many people with gastritis experience no symptoms at all. However, upper central abdominal pain is the most common symptom; the pain may be dull, vague, burning, aching, gnawing, sore, or sharp. Pain is usually located in the upper central portion of the abdomen, but it may occur anywhere from the upper left portion of the abdomen around to the back. Other signs and symptoms may include the following:

Nausea
Vomiting (may be clear, green or yellow, blood-streaked or completely bloody depending on the severity of the stomach inflammation)
Belching (does not usually relieve stomach pain if present)
Bloating
Early satiety
Loss of appetite
Unexplained weight loss

Causes
There are two categories of gastritis depending on the cause of the disease. There is erosive gastritis, for which the common causes are stress, alcohol, some drugs, such as aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), and Crohns disease. And, there is non-erosive gastritis, for which the most common cause is a Helicobacter pylori infection.
These scores (0–3) are used in the OLGA staging assessment in each 10 compartment:

Treatment
Antacids are a common treatment for mild to medium gastritis. When antacids do not provide enough relief, medications such as H2 blockers and proton-pump inhibitors that help reduce the amount of acid are often prescribed.Cytoprotective agents are designed to help protect the tissues that line the stomach and small intestine. They include the medications sucralfate and misoprostol. If NSAIDs are being taken regularly, one of these medications to protect the stomach may also be taken. Another cytoprotective agent is bismuth subsalicylateSeveral regimens are used to treat H. pylori infection. Most use a combination of two antibiotics and a proton pump inhibitor. Sometimes bismuth is added to the regimen. History
In 1,000 A.D, Avicenna first gave the description of stomach cancer. In 1728, German physician Georg Ernst Stahl first coined the term "gastritis". Italian anatomical pathologist Giovanni Battista Morgagni further described the characteristics of gastric inflammation. He described the characteristics of erosive or ulcerative gastritis and erosive gastritis. Between 1808 and 1831, French physician François-Joseph-Victor Broussais gathered information from the autopsies of dead French soldiers. He described chronic gastritis as "Gastritide" and erroneously believed that gastritis was the cause of ascites, typhoid fever, and meningitis. In 1854, Charles Handfield Jones and Wilson Fox described the microscopic changes of stomach inner lining in gastritis which existed in diffuse and segmental forms. In 1855, Baron Carl von Rokitansky first described hypertrophic gastritis. In 1859, British physician, William Brinton first described about acute, subacute, and chronic gastritis.