Corticosteroids are the mainstay of therapy with a 90% response rate in some studies. Appropriate duration of steroid treatment is unknown and relapse often necessitates long term treatment. Various steroid sparing agents e.g. sodium cromoglycate (a stabilizer of mast cell membranes), ketotifen (an antihistamine), and montelukast (a selective, competitive leukotriene receptor antagonist) have been proposed, centering on an allergic hypothesis, with mixed results. An elimination diet may be successful if a limited number of food allergies are identified.

Treatment strategies may include medication, dietary modification to exclude food allergens, and mechanical dilatation of the esophagus.

The current recommendation for first line treatment is PPI in lieu of diet as more than half of people with EOE respond to this, and it is a low risk, low cost treatment. The next step treatment is topical corticosteroids (topical viscous budesonide or fluticasone).

Dietary treatment can be effective, as there does appear to be a role of allergy in the development of EOE. Allergy testing is not particularly effective in predicting which foods are driving the disease process. Various approaches have been tried, where either six food groups (cow´s milk, wheat, egg, soy, nuts and fish/seafood), four groups (animal milk, gluten-containing cereals, egg, legumes) or two groups (animal milk and gluten-containing cereals) are excluded for a period of time, usually six weeks. Endoscopy is required to measure the response to the dietary measure. A "top down" (starting with six foods, then reintroducing) approach may be very restrictive. Four- or even two-group exclusion diets may be less difficult to follow and reduce the need for many endoscopies if the response to the limited restriction is good.

Endoscopic dilatation is sometimes required if there is significant narrowing of the esophagus. This is effective in 84% of people who require this procedure.

Mild cases usually do not require treatment and will go away after a few days in healthy people. In cases where symptoms persist or when it is more severe, specific treatments based on the initial cause may be required.

In cases where diarrhoea is present, replenishing fluids lost is recommended, and in cases with prolonged or severe diarrhoea which persists, intravenous rehydration therapy or antibiotics may be required. A simple oral rehydration therapy (ORS) can be made by dissolving one teaspoon of salt, eight teaspoons of sugar and the juice of an orange into one litre of clean water. Studies have shown the efficacy of antibiotics in reducing the duration of the symptoms of infectious enteritis of bacterial origin, however antibiotic treatments are usually not required due to the self-limiting duration of infectious enteritis.

Antibiotics are not usually used for gastroenteritis, although they are sometimes recommended if symptoms are particularly severe or if a susceptible bacterial cause is isolated or suspected. If antibiotics are to be employed, a macrolide (such as azithromycin) is preferred over a fluoroquinolone due to higher rates of resistance to the latter. Pseudomembranous colitis, usually caused by antibiotic use, is managed by discontinuing the causative agent and treating it with either metronidazole or vancomycin. Bacteria and protozoans that are amenable to treatment include "Shigella" "Salmonella typhi", and "Giardia" species. In those with "Giardia" species or "Entamoeba histolytica", tinidazole treatment is recommended and superior to metronidazole. The World Health Organization (WHO) recommends the use of antibiotics in young children who have both bloody diarrhea and fever.

Antiemetic medications may be helpful for treating vomiting in children. Ondansetron has some utility, with a single dose being associated with less need for intravenous fluids, fewer hospitalizations, and decreased vomiting. Metoclopramide might also be helpful. However, the use of ondansetron might possibly be linked to an increased rate of return to hospital in children. The intravenous preparation of ondansetron may be given orally if clinical judgment warrants. Dimenhydrinate, while reducing vomiting, does not appear to have a significant clinical benefit.

The body can usually fight off the disease on its own. The most important factor when treating gastroenteritis is the replacement of fluids and electrolytes that are lost because of the diarrhea and vomiting.

Antibiotics will not be effective if the cause of gastroenteritis is a viral infection. Doctors usually do not recommend antidiarrheal medications (e.g., Loperamide) for gastroenteritis because they tend to prolong infection, especially in children.

Parasitic infections are difficult to treat. A number of drugs are available once the condition has been identified. Removing part of the colon or needle aspiration of abscesses in liver may be required.

Treatment is directed toward the underlying cause. However, in primary eosinophilia, or if the eosinophil count must be lowered, corticosteroids such as prednisone may be used. However, immune suppression, the mechanism of action of corticosteroids, can be fatal in patients with parasitosis.

Due to its rarity, no comprehensive treatment studies on eosinophilic myocarditis have been conducted. Small studies and case reports have directed efforts towards: a) supporting cardiac function by relieving heart failure and suppressing life-threatening abnormal heart rhythms; b) suppressing eosinophil-based cardiac inflammation; and c) treating the underlying disorder. In all cases of symptomatic eosinophilic myocarditis that lack specific treatment regimens for the underlying disorder, available studies recommend treating the inflammatory component of this disorder with non-specific immunosuppressive drugs, principally high-dosage followed by slowly-tapering to a low-dosage maintenance corticosteroid regimens. It is recommended that afflicted individuals who fail this regimen or present with cardiogenic shock be treated with other non-specific immunosuppressive drugs viz., azathioprine or cyclophosphamide, as adjuncts to, or replacements for, corticosteroids. However, individuals with an underlying therapeutically accessible disease should be treated for this disease; in seriously symptomatic cases, such individuals may be treated concurrently with a corticosteroid regimen. Examples of diseases underlying eosinophilic myocarditis that are recommended for treatments directed at the underlying disease include:

- Infectious agents: specific drug treatment of helminth and protozoan infections typically takes precedence over non-specific immunosuppressive therapy, which, if used without specific treatment, could worsen the infection. In moderate-to-severe cases, non-specific immunosuppression is used in combination with specific drug treatment.

- Toxic reactions to ingested agents: discontinuance of the ingested agent plus corticosteroids or other non-specific immunosuppressive regimens.

- Clonal eosinophilia caused by mutations in genes that are highly susceptible to tyrosine kinase inhibitors such as "PDGFRA", "PDGFRB", or possibly "FGFR1": first generation tyrosine kinase inhibitors (e.g. imatinib) are recommended for the former two mutations; a later generation tyrosine kinase inhibitors, ponatinib, alone or combined with bone marrow transplantation, may be useful for treating the FGFR1 mutations.

- Clonal hypereosinophilia due to mutations in other genes or primary malignancies: specific treatment regimens used for these pre-malignant or malignant diseases may be more useful and necessary than non-specific immunosuppression.

- Allergic and autoimmune diseases: non-specific treatment regimens used for these diseases may be useful in place of a simple corticosteroid regimen. For example, eosinophilic granulomatosis with polyangiitis can be successfully treated with mepolizumab.

- Idiopathic hypereosinphilic syndrome and lymphocyte-variant hypereosinophilia: corticosteroids; for individuals with these hypereosinophilias that are refractory to or break through corticosteroid therapy and individuals requiring corticosteroid-sparing therapy, recommended alternative drug therapies include hydroxyurea, Pegylated interferon-α, and either one of two tyrosine kinase inhibitors viz., imatinib and mepolizumab).

Depending on the cause of the inflammation, symptoms may last from one day to more than a week.

Gastroenteritis caused by viruses may last one to two days. Most people recover easily from a short episode of vomiting and diarrhea by drinking clear fluids to replace the fluid that was lost and then gradually progressing to a normal diet. But for others, especially infants and the elderly, the loss of bodily fluid with gastroenteritis can cause dehydration, which can be a life-threatening illness unless it is treated and fluids in the body are replaced.

Treatments for esophagitis include medications to block acid production, to manage pain, and to reduce inflammation. Other treatments include antibiotics and intravenous nutrition.

To treat reflux esophagitis, over the counter antacids, medications that reduce acid production (H-2 receptor blockers), and proton pump inhibitors are recommended to help block acid production and to let the esophagus heal. Some prescription medications to treat reflux esophagitis include higher dose H-2 receptor blockers, proton pump inhibitors, and prokinetics, which help with the emptying of the stomach.

To treat eosinophilic esophagitis, avoiding any allergens that may be stimulating the eosinophils is recommended. As for medications, proton pump inhibitors and steroids can be prescribed. Steroids that are used to treat asthma can be swallowed to treat eosinophil esophagitis due to nonfood allergens. The removal of food allergens from the diet is included to help treat eosinophilic esophagitis.

For infectious esophagitis, a medicine is prescribed based on what type of infection is causing the esophagitis. These medicines are prescribed to treat bacterial, fungal, viral, and/or parasitic infections.

An endoscopy can be used to remove ill fragments. Surgery can be done to remove the damaged part of the esophagus. For reflux esophagitis, a fundooplication can be done to help strengthen the lower esophageal sphincter from allowing backflow of the stomach into the esophagus. As for patients that have a narrowing esophagus, a gastroenterologist can perform a procedure to dilate the esophagus.

Some home remedies and lifestyle changes to help with esophagitis include losing weight, stop smoking, lowering stress, avoid sleeping/lying down after eating, raise your head while laying down, taking medicines correctly, avoiding certain medications, and avoiding foods that cause the reflux that might be causing the esophagitis.

If the disease remains untreated, it can cause scarring and discomfort in the esophagus. If the irritation is not allowed to heal, esophagitis can result in esophageal ulcers. Esophagitis can develop into Barrett's esophagus and can increase the risk of esophageal cancer.

The prognosis for a person with esophagitis depends on the underlying causes and conditions. If a patient has a more serious underlying cause such as a digestive system or immune system issue, it may be more difficult to treat. Normally, the prognosis would be good with no serious illnesses. If there are more causes than one, the prognosis could move to fair.

Treatment primarily consists of reducing eosinophil levels and preventing further damage to organs. Corticosteroids, such as Prednisone, are good for reducing eosinophil levels and antineoplastics are useful for slowing eosinophil production. Surgical therapy is rarely utilised, however splenectomy can reduce the pain due to spleen enlargement. If damage to the heart (in particular the valves), then prosthetic valves can replace the current organic ones. Follow-up care is vital for the survival of the patient, as such the patient should be checked for any signs of deterioration regularly. After promising results in drug trials (95% efficiency in reducing blood eosinophil count to acceptable levels) it is hoped that in the future hypereosinophilic syndrome, and diseases related to eosinophils such as asthma and eosinophilic granulomatosis with polyangiitis, may be treated with the monoclonal antibody Mepolizumab currently being developed to treat the disease. If this becomes successful, it may be possible for corticosteroids to be eradicated and thus reduce the amount of side effects encountered.

Treatment for eosinophilic granulomatosis with polyangiitis includes glucocorticoids (such as prednisolone) and other immunosuppressive drugs (such as azathioprine and cyclophosphamide). In many cases, the disease can be put into a type of chemical remission through drug therapy, but the disease is chronic and lifelong.

A systematic review conducted in 2007 indicated all patients should be treated with high-dose steroids, but in patients with a five-factor score of one or higher, cyclophosphamide pulse therapy should be commenced, with 12 pulses leading to fewer relapses than six. Remission can be maintained with a less toxic drug, such as azathioprine or methotrexate.

On December 12, 2017, the FDA approved mepolizumab, the first drug therapy specifically indicated for the treatment of eosinophilic granulomatosis with polyangiitis. Patients taking mepolizumab experienced a "significant improvement" in their symptoms.

When eosinophilic pneumonia is related to an illness such as cancer or parasitic infection, treatment of the underlying cause is effective in resolving the lung disease. When due to AEP or CEP, however, treatment with corticosteroids results in a rapid, dramatic resolution of symptoms over the course of one or two days. Either intravenous methylprednisolone or oral prednisone are most commonly used. In AEP, treatment is usually continued for a month after symptoms disappear and the x-ray returns to normal (usually four weeks total). In CEP, treatment is usually continued for three months after symptoms disappear and the x-ray returns to normal (usually four months total). Inhaled steroids such as fluticasone have been used effectively when discontinuation of oral prednisone has resulted in relapse.

Because EP affects the lungs, individuals with EP have difficulty breathing. If enough of the lung is involved, it may not be possible for a person to breathe without support. Non-invasive machines such as a bilevel positive airway pressure machine may be used. Otherwise, placement of a breathing tube into the mouth may be necessary and a ventilator may be used to help the person breathe.

Treatment of acute rotavirus infection is nonspecific and involves management of symptoms and, most importantly, maintenance of hydration. If untreated, children can die from the resulting severe dehydration. Depending on the severity of diarrhea, treatment consists of oral rehydration, during which the child is given extra water to drink that contains small amounts of salt and sugar. Some infections are serious enough to warrant hospitalisation where fluids are given by intravenous drip or nasogastric tube, and the child's electrolytes and blood sugar are monitored. Antibiotics are not recommended.

Rotavirus infections rarely cause other complications and for a well managed child the prognosis is excellent.

The standard treatment of food bolus obstruction is the use of endoscopy or fibre-optic cameras inserted by mouth into the esophagus. Endoscopes can be used to diagnose the cause of the food bolus obstruction, as well as to remove the obstruction. Traditional endoscopic techniques involved the use of an overtube, a plastic tube inserted into the esophagus prior to the removal of the food bolus, in order to reduce the risk of aspiration into the lungs at the time of endoscopy. However, the "push technique", which involves insufflating air into the esophagus, and gently pushing the bolus toward the stomach instead, has emerged as a common and safe way of removing the obstruction.

Other tools may be used to remove food boluses. The Roth Net® is a mesh net that can be inserted through the endoscope, and opened and closed from the outside; it can be used to retrieve pieces of obstructed food. Snares, which are normally used to remove polyps can be used to macerate the food causing the obstruction. Dormia baskets, which are metal baskets used to remove stones from the common bile duct in a procedure known as endoscopic retrograde cholangiopancreatography, can be opened and closed from the outside in a similar manner to macerate food and facilitate removal. Forceps used for biopsies can also be employed in a similar manner.

Eosinophilic gastroenteritis (EG) is a rare and heterogeneous condition characterized by patchy or diffuse eosinophilic infiltration of gastrointestinal (GI) tissue, first described by Kaijser in 1937. Presentation may vary depending on location as well as depth and extent of bowel wall involvement and usually runs a chronic relapsing course. It can be classified into mucosal, muscular and serosal types based on the depth of involvement. Any part of the GI tract can be affected, and isolated biliary tract involvement has also been reported.

The stomach is the organ most commonly affected, followed by the small intestine and the colon.

Ligneous conjunctivitis may be managed by topical treatments of plasminogen, topical and subconjunctival fresh frozen plasma, and fibrinolytic therapy.

The basis of management is to find and correct the underlying cause. Many times cats with EGC will respond to treatment with corticosteroids or to ciclosporin.

Enteritis is inflammation of the small intestine. It is most commonly caused by food or drink contaminated with pathogenic microbes. but may have other causes such as NSAIDs, cocaine, radiation therapy as well as autoimmune conditions like Crohn's disease and coeliac disease. Symptoms include abdominal pain, cramping, diarrhoea, dehydration, and fever. Related diseases include inflammation of the stomach (gastritis) and large intestine (colitis).

Duodenitis, jejunitis and ileitis are subtypes of enteritis which are only localised to a specific part of the small intestine. Inflammation of both the stomach and small intestine is referred to as gastroenteritis. Inflammation of related organs of the gastrointestinal system are:

- gastritis

- gastroenteritis

- colitis

- enterocolitis

In a "hemodynamically significant" case of hematemesis, that is hypovolemic shock, resuscitation is an immediate priority to prevent cardiac arrest. Fluids and/or blood is administered, preferably by large bore intravenous cannula, and the patient is prepared for emergency endoscopy, which is typically done in theatres. Surgical opinion is usually sought in case the source of bleeding cannot be identified endoscopically, and laparotomy is necessary.

Securing the airway is a top priority in hematemesis patients, especially those with a disturbed conscious level (hepatic encephalopathy in esophageal varices patient.) A cuffed endotracheal tube could be a life saving choice.

Treatment of eosinophilic folliculitis in people with HIV typically begins with the initiation of Highly Active Anti-Retroviral Therapy in order to help reconstitute the immune system. Direct treatment of the EF itself focuses on decreasing the inflammation and itching. Topical corticosteroids and oral antihistamines can alleviate the itching and decrease the size and number of lesions. Treatment with the antifungal drug itraconazole, the antibiotic metronidazole, and the anti-mite drug permethrin may lead to some improvement of symptoms. Other therapies include PUVA, topical tacrolimus, and isotretinoin.

Eosinophilic esophagitis (EoE, also spelled eosinophilic oesophagitis), also known as allergic oesophagitis, is an allergic inflammatory condition of the esophagus that involves eosinophils, a type of white blood cell. Symptoms are swallowing difficulty, food impaction, vomiting, and heartburn.

Eosinophilic esophagitis was first described in children but also occurs in adults. The condition is not well understood, but food allergy may play a significant role. The treatment may consist of removal of known or suspected triggers and medication to suppress the immune response. In severe cases, it may be necessary to stretch the esophagus with an endoscopy procedure.

If this is not the case, the patient is generally administered a proton pump inhibitor (e.g. omeprazole), given blood transfusions (if the level of hemoglobin is extremely low, that is less than 8.0 g/dL or 4.5–5.0 mmol/L), and kept NPO, which stands for "nil per os" (Latin for "nothing by mouth", or no eating or drinking) until endoscopy can be arranged. Adequate venous access (large-bore cannulas or a central venous catheter) is generally obtained in case the patient suffers a further bleed and becomes unstable.

Treatment of acute rotavirus infection is nonspecific and involves management of symptoms and, most importantly, management of dehydration. If untreated, children can die from the resulting severe dehydration. Depending on the severity of diarrhoea, treatment consists of oral rehydration therapy, during which the child is given extra water to drink that contains specific amounts of salt and sugar. In 2004, the World Health Organisation (WHO) and UNICEF recommended the use of low-osmolarity oral rehydration solution and zinc supplementation as a two-pronged treatment of acute diarrhoea. Some infections are serious enough to warrant hospitalisation where fluids are given by intravenous therapy or nasogastric intubation, and the child's electrolytes and blood sugar are monitored. Probiotics have been shown to reduce the duration of rotavirus diarrhoea, and according to the European Society for Pediatric Gastroenterology "effective interventions include administration of specific probiotics such as "Lactobacillus rhamnosus" or "Saccharomyces boulardii", diosmectite or racecadotril." Rotavirus infections rarely cause other complications and for a well managed child the prognosis is excellent.

Treatments are generally directed toward stopping the inflammation and suppressing the immune system. Typically, corticosteroids such as prednisone are used. Additionally, other immune suppression drugs, such as cyclophosphamide and others, are considered. In case of an infection, antimicrobial agents including cephalexin may be prescribed. Affected organs (such as the heart or lungs) may require specific medical treatment intended to improve their function during the active phase of the disease.