Gastritis is an inflammation of the lining of the stomach. The inflammatory lesions may be either acute or chronic. This condition occurs when white blood cells move into the wall of stomach due to some injury. In some cases, gastritis can lead to ulcers and an increased risk of stomach cancer. For most people, however, gastritis isn't serious and improves quickly with treatment. Gastritis is a common medical problem. Up to 10% of people who come to a hospital emergency department with abdominal pain have gastritis. Gastritis can be caused by drinking too much alcohol, coffee and acidic beverages, prolonged use of nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen, or infection with bacteria such as Helicobacter pylori (H. pylori). Sometimes gastritis develops after major surgery, traumatic injury, burns, or severe infections. Certain diseases, such as pernicious anemia, stress, autoimmune disorders, and chronic bile reflux, can cause gastritis as well. The most common symptoms are abdominal upset or pain. Other symptoms can be  belching, abdominal bloating, nausea, hiccups, loss of appetite and vomiting or a feeling of fullness or of burning in the upper abdomen. Blood in your vomit or black stools may be a sign of bleeding in the stomach, which may indicate a serious problem requiring immediate medical attention.

HOME REMEDIES

A teaspoon of ajwain (Carom seeds) with a pinch of salt is one of the effective home remedies for gastritis.
One should make it a habit to chew roasted fennel (saunf) after meals, if he suffers from gastritis.
The herb marigold is also considered beneficial in the treatment of gastritis. An infusion of the herb in doses of a tablespoon may be taken twice daily.
A fresh ginger if chewed before taking meals stimulates digestion, thus preventing gastritis.
Omega-3 fatty acids, such as fish oil, 1 - 2 capsules or 1 tablespoonful oil 2 - 3 times daily -- may help decrease inflammation. Fish oil may increase the risk of bleeding.
Papaya seeds and pineapple aid digestion. It should be slightly ripe. Papaya is rich in digestive enzymes.
Carrot juice mixed with spinach juice in equal amount is the excellent remedy for treating gastritis.
Take Artichoke if you feel abdominal pain, bloating or to relive vomiting, and nausea. 
One or two pieces of garlic rolled in dry grape without seeds, immediately provides relief from the condition. Another natural remedy for gastritis.
Mix Sprague powder six parts and black salt one part. Take 2 grams of the mixture with warm water.
Probiotic supplement (containing Lactobacillus acidophilus ), 5 - 10 billion CFUs (colony forming units) a day -- Probiotics or “friendly” bacteria may help maintain a balance in the digestive system between good and harmful bacteria such as H. pylori.
Tamarind water should be taken along with asafoetida and cumin water.
Cranberry (Vaccinium macrocarpon) 400 mg twice daily -- Some preliminary research suggests cranberry may inhibit H. pylori growth in the stomach.
One cup of rice gruel is recommended for gastritis it should be twice a day regularly.
Potato juice has been found valuable in relieving gastritis. The recommended dose is half a cup of the juice, two or three times daily, half an hour before meals.
Eating jaggery after every meal, it provides you relief from gastric problems.
Marshmallow relives nausea, indigestion, gastritis and ulcers.
Mastic (Pistacia lentiscus) standardized extract, 1,000 - 2,000 mg daily in divided dosages -- Mastic is a traditional treatment for peptic ulcers and inhibits.
Amalaki (amla) is a carminative and stomachic. It is used in Ayurveda as a cardiotonic, aphrodisiac, antipyretic, antidiabetic, cerebral and gastrointestinal tonic.
Peppermint contains volatile oils like menthol, relives indigestion, gastritis and stomach ulcers. 
Take a few figs and immerse it in warm water. After about 10 minutes, strain this water and drink it.
Take a piece of cardamom and one clove. Crush both to make a powder. Put this powder in your mouth. It is not only a great cure for gastritis but it is also a good mouth freshener.
Take 2 teaspoons of peach leaves in a cup and add boiling water to it. After about 10 minutes, drink this concoction. Have this mixture thrice a day.
Chewing roasted fennel after meals also imparts relief from gastritis.
Goldenseal destroys bacteria that cause gastritis, stomach inflammation and ulcers.
Eat two plantains every morning and after 10 minutes drink a glassful of milk. You can continue the process for some days. It is an effective remedy to permanently treat gastritis.
Use of buttermilk and curd along with asafoetida and cumin water is highly beneficial and is one of the effective home remedies for gastritis.
Honey is also used as an effective home remedy for the patient suffering from gastritis.
Coconut water greatly helps in bringing the normal condition of the stomach within a few hours.
In a cup of hot water put half a teaspoon of licorice root tea. Wait for 10 minutes, strain the tea and drink. Repeat this at least 3 times daily.
125 grams of curd, 2 grams of Sprague and half gram of black salt taken together also provides relief from gastritis and is goodhome remedy for gastritis.
Application of heat with a hot compress or hot water bottle, twice a daily, either on an empty stomach or two hours after meals, will also be beneficial.
Eight to ten glasses of water should be taken daily but water should not be taken with meals as it dilutes the digestive juices and delays digestion. Haste should be avoided while eating
Take an orange and extract juice from it. Add some roasted cumin seeds and a pinch of rock salt in it. Drink the mixture whenever you are facing problem of gastritis.
Lemon juice is also an effective remedy for thetreatment of gastritis.
He should, however, undertake breathing and other light exercises like walking, swimming, and golf.
Eliminate dairy products from your diet until the digestive system is healed. 
Take 400 IU a day of vitamin E to reduce inflammation in the stomach.
Take four-five leaves of holy basil. Wash them and chew them slowly so that their juices are introduced in stomach.
Eat proper amount of cabbage, then it ensures proper motions. If the motions are coming properly then there is no gas expelled from the body.
Patient should be given balanced diet containing cereals, grams, green leafy vegetable, juicy fruits, etc.