Acute Gastritis

What Is It, Causes, Symptoms, Diagnosis, and More

Author: Anna Hernández, MD

Editors: Ahaana Singh, Lisa Miklush, PhD, RN, CNS

Illustrator: Jillian Dunbar

What is acute gastritis?

Acute gastritis refers to a sudden onset of inflammation of the stomach lining, also known as the gastric mucosa. In contrast, chronic gastritis refers to long-lasting inflammation of the gastric mucosa.  

With acute gastritis, a disruption in the gastric mucosa triggers an inflammatory immune response that attracts white blood cells to the site of injury. If the mucosal damage is severe enough, acute gastritis can progress to erosive gastritis, which consists of shallow lesions of the stomach lining (i.e.,  gastric erosions), painful ulcerations or sores, and small areas of bleeding within the mucosa. 

Although the word “gastritis” is sometimes used as a synonym for “upset stomach” or “indigestion,” it most accurately refers to the evidence of inflammatory cells in a stomach biopsy, usually obtained through an upper endoscopy. An endoscopy is a minimally invasive procedure that uses a flexible tube attached to a small camera to look at the inside of a part of the body, like the gastrointestinal tract. If no inflammation is seen on the gastric biopsy, then the term gastropathy can be used instead. 

What causes acute gastritis?

Acute gastritis occurs as a result of weakness or injury to the gastric mucosa, which can allow stomach acids to further damage and inflame the lining. There are several risk factors for damage of the gastric mucosa, including use of certain medications, infections, acute stress, and dietary factors. 

One of the main causes of acute gastritis is frequent or long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen. These medications interfere with the protective mechanisms of the gastric mucosa, leading to a decreased production of gastric mucus and increased vulnerability to gastric acid. As a result, excessive use of NSAIDs can increase the risk of developing acute gastritis. 

Bacterial infection by Helicobacter pylori (H. pylori) is another common cause of gastritis. H. pylori is a spiral-shaped bacteria that colonizes the stomach of many individuals. In most people, early infection by H. pylori does not cause many symptoms and usually goes unnoticed. However, long-lasting or chronic infection by H. pylori can lead to persistent inflammation of the gastric mucosa, as well as loss of the normal glandular structure of the stomach. Eventually, this can increase the risk of developing other digestive problems, such as stomach ulcers and stomach cancer

Acute gastritis can also occur as a result of extreme physiological stress, often due to major surgery, trauma, severe burns, or severe illnesses. In some cases, the stomach ulcers associated with specific types of physiological stress are given specific names, such as Curling ulcers (associated with severe burns) and Cushing ulcers (associated with brain injury). 

Additional risk factors for developing acute gastritis include increased intake of alcohol and caffeine and exposure to cigarette smoke, all of which can irritate the gastric mucosa. More rarely, the ingestion of harsh chemicals can lead to severe mucosal damage due to a direct gastric injury. 

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How long does acute gastritis last?

Acute gastritis usually lasts for a short period of time. In most cases, it resolves spontaneously within a few days or weeks once the inflammation has settled. In other cases, however, acute gastritis can lead to recurrent or long-term inflammation of the gastric mucosa, otherwise known as chronic gastritis. With time, chronic gastritis can increase the risk of developing other complications, such as stomach ulcers, upper gastrointestinal bleeding, and certain types of stomach cancer.

What are the signs and symptoms of acute gastritis?

Most individuals with acute gastritis are asymptomatic or experience mild symptoms, such as loss of appetite, upper abdominal discomfort, belching, nausea, and vomiting. In more severe cases, some individuals may experience upper gastrointestinal bleeding due to gastric erosions and ulcerations of the mucosa. In turn, this can lead to hematemesis, or vomiting blood, as well as melena, which are smelly, black stools caused by the digestion of blood in the gastrointestinal tract

How is acute gastritis diagnosed?

Initially, an assessment of the individual’s medical history is performed to identify possible causes of acute gastritis, such as long-term use of NSAIDs, excessive alcohol consumption, or H. pylori infection. Since acute gastritis is often self-resolving, if a clear cause of inflammation can be identified and treated successfully, no additional tests may be required. However, if the diagnosis is uncertain, or if bleeding occurs, an upper endoscopy may be performed to take a direct look at the gastric mucosa and obtain a biopsy sample to examine. 

How is acute gastritis treated?

Treatment of acute gastritis is aimed at relieving the underlying cause of inflammation. Some cases of acute gastritis resolve without any treatment, while others require treatment via lifestyle changes or medications.

Proton-pump inhibitors, such as omeprazole or pantoprazole, may aid in relieving the symptoms of gastritis  by helping decrease gastric acid production. Proton-pump inhibitors, along with a combination of various antibiotics, can also be used to treat H. pylori infection. Along with proton-pump inhibitors, medication may feature antacids, including H2 blockers (e.g., cimetidine, ranitidine, or famotidine) and some over-the-counter medications, such as bismuth subsalicylate and calcium carbonate

It is also important, when possible, to remove or avoid any risk factors that may contribute to the inflammation. This may include ceasing use of nonsteroidal anti-inflammatory drugs (NSAIDs), reducing alcohol and caffeine intake, or quitting smoking

What should you eat if you have acute gastritis?

Individuals with acute gastritis may be advised to make certain dietary changes, such as eating a bland diet consisting of soups, vegetables, lean meats, fish, and non-carbonated drinks. Other recommendations include avoiding irritating foods (e.g., spicy or fatty foods), eating more frequent and smaller meals, and reducing the intake of alcohol and caffeine

What are the most important facts to know about acute gastritis?

Acute gastritis refers to a sudden onset inflammation of the stomach lining that results from a disruption to the gastric mucosa that allows for further damage and inflammation from stomach acids. There are many risk factors that can lead to acute gastritis, such as long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs), infection by Helicobacter pylori bacteria, increased intake of alcohol or caffeine, and severe physiological stress, among others. Common symptoms of acute gastritis include stomach discomfort, loss of appetite, nausea, and vomiting. In severe cases, ulceration and gastrointestinal bleeding may also occur. Diagnosis of acute gastritis is usually based on an assessment of medical history, although in some cases, it can be confirmed by demonstrating inflammatory changes through a biopsy of the gastric mucosa. Treatment of acute gastritis depends on the underlying cause of inflammation and may include lifestyle changes, acid-reducing medications, or antibiotics.

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Related links

Acid reducing medications
GERD, peptic ulcers, gastritis, and stomach cancer: Pathology review
Gastrointestinal bleeding: Pathology review
Helicobacter pylori
Peptic ulcers and stomach cancer: Clinical practice

Resources for research and reference

Chey WD, Leontiadis GI, Howden CW, Moss SF. ACG clinical guideline: treatment of Helicobacter pylori infection [published correction appears in American Journal of Gastroenterology. 2018 Jul;113(7):1102]. American Journal of Gastroenterology. 2017;112(2):212-239. doi:10.1038/ajg.2016.563

Drini M. Peptic ulcer disease and non-steroidal anti-inflammatory drugs. Australian Prescriber. 2017;40(3):91-93. doi:

Kumar V, Abbas AK, Aster JC, Perkins JA, Robbins SL. Robbins Basic Pathology. 9th ed. Philadelphia, Pa Elsevier, Saunders; 2013.

Watari J, Chen N, Amenta PS, et al. Helicobacter pylori associated chronic gastritis, clinical syndromes, precancerous lesions, and pathogenesis of gastric cancer development. World Journal of Gastroenterology. 2014;20(18):5461-5473. doi:10.3748/wjg.v20.i18.5461