Except in the most severe cases, ischemic colitis is treated with supportive care. IV fluids are given to treat dehydration, and the patient is placed on bowel rest (meaning nothing to eat or drink) until the symptoms resolve. If possible, cardiac function and oxygenation should be optimized to improve oxygen delivery to the ischemic bowel. A nasogastric tube may be inserted if an ileus is present.

Antibiotics are sometimes given in moderate to severe cases; the data supporting this practice date to the 1950s, although there is more recent animal data suggesting that antibiotics may increase survival and prevent bacteria from crossing the damaged lining of the colon into the bloodstream. The use of prophylactic antibiotics in ischemic colitis has not been prospectively evaluated in humans, but many authorities recommend their use based on the animal data.

Patients being treated supportively are carefully monitored. If they develop worsening symptoms and signs such as high white blood cell count, fever, worsened abdominal pain, or increased bleeding, then they may require surgical intervention; this usually consists of laparotomy and bowel resection.

The treatment of mesenteric ischemia depends on the cause, and can be medical or surgical. However, if bowel has become necrotic, the only treatment is surgical removal of the dead segments of bowel.

In non-occlusive mesenteric ischemia, where there is no blockage of the arteries supplying the bowel, the treatment is medical rather than surgical. People are admitted to the hospital for resuscitation with intravenous fluids, careful monitoring of laboratory tests, and optimization of their cardiovascular function. NG tube decompression and heparin anticoagulation may also be used to limit stress on the bowel and optimize perfusion, respectively.

Surgical revascularisation remains the treatment of choice for mesenteric ischaemia related to an occlusion of the vessels supplying the bowel, but thrombolytic medical treatment and vascular interventional radiological techniques have a growing role.

If the ischemia has progressed to the point that the affected intestinal segments are gangrenous, a bowel resection of those segments is called for. Often, obviously dead segments are removed at the first operation, and a second-look operation is planned to assess segments that are borderline that may be savable after revascularization.

The objective of treatment is to decompress the bowel and to prevent swallowed air from further distending the bowel. If decompression is not achieved or the patient does not improve within 24 hours, a colectomy (surgical removal of all or part of the colon) is indicated. When surgery is required the recommended procedure is a subtotal colectomy with end ileostomy. Fluid and electrolyte replacement help to prevent dehydration and shock. Use of corticosteroids may be indicated to suppress the inflammatory reaction in the colon if megacolon has resulted from active inflammatory bowel disease. Antibiotics may be given to prevent sepsis.

If the condition does not improve, the risk of death is significant. In case of poor response to conservative therapy, a colectomy is usually required.

Lymphocytic and collagenous colitis have both been shown in randomized, placebo-controlled trials to respond well to budesonide, a glucocorticoid. Budesonide formulated to be active in the distal colon and rectum is effective for both active disease and in the prevention of relapse. However, relapse occurs frequently after withdrawal of therapy.

Studies of a number of other agents including antidiarrheals, bismuth subsalicylate (Pepto-Bismol), mesalazine/mesalamine (alone or in combination with cholestyramine), systemic corticosteroids, cholestyramine, immunomodulators, and probiotics have shown to be less effective than budesonide for treating both forms of microscopic colitis.

Anti-TNF inhibitors. split ileostomy, diverting ileostomy, and subtotal colectomy are options for management of steroid-dependent or refractory microscopic colitis. Currently, the need to resort to surgery is limited considering the improvement of drug therapy options. However, surgery is still considered for patients with severe, unresponsive microscopic colitis.

Ulcerative colitis can be treated with a number of medications, including 5-ASA drugs such as sulfasalazine and mesalazine. Corticosteroids such as prednisone can also be used due to their immunosuppressive and short-term healing properties, but because their risks outweigh their benefits, they are not used long-term in treatment. Immunosuppressive medications such as azathioprine and biological agents such as infliximab and adalimumab are given only if people cannot achieve remission with 5-ASA and corticosteroids. Such treatments are used less commonly due to their possible risk factors, including but not limited to increased risk of cancers in teenagers and adults, tuberculosis, and new or worsening heart failure (these side effects are rare). A formulation of budesonide was approved by the FDA for treatment of active ulcerative colitis in January 2013. The evidence on methotrexate does not show a benefit in producing remission in people with ulcerative colitis. Off-label use of drugs such as ciclosporin and tacrolimus has shown some benefits. Fexofenadine, an antihistamine drug used in treatment of allergies, has shown promise in a combination therapy in some studies. Opportunely, low gastrointestinal absorption (or high absorbed drug gastrointestinal secretion) of fexofenadine results in higher concentration at the site of inflammation. Thus, the drug may locally decrease histamine secretion by involved gastrointestinal mast cells and alleviate the inflammation.

Sulfasalazine has been a major agent in the therapy of mild to moderate ulcerative colitis for over 50 years. In 1977, Mastan S. Kalsi "et al." determined that 5-aminosalicylic acid (5-ASA and mesalazine) was the therapeutically active component in sulfasalazine. Since then, many 5-ASA compounds have been developed with the aim of maintaining efficacy but reducing the common side effects associated with the sulfapyridine moiety in sulfasalazine.

Many people with diverticulosis have minimal to no symptoms, and do not require any specific treatment. Colonic stimulants should be avoided. Treatments, like some colon cleansers, that cause hard stools, constipation, and straining, are not recommended.

Complicated diverticulosis requires treatment of the complication. These complications are often grouped under a single diagnosis of diverticulitis and require skilled medical care of the infection, bleeding and perforation which may include intensive antibiotic treatment, intravenous fluids and surgery. Complications are more common in patients who are taking NSAIDs or aspirin. As diverticulosis occurs in an older population such complications are serious events.

It usually resolves with conservative therapy stopping oral ingestions, i.e. nil per os and a nasogastric tube, but may require colonoscopic decompression which is successful in 70% of the cases. A study published in the "New England Journal of Medicine" showed that neostigmine is a potent pharmacological way of decompressing the colon. According to the American Society for Gastrointestinal Endoscopy (ASGE), it should be considered prior to colonoscopic decompression. The use of neostigmine is not without risk since it can induce bradyarrhythmia and bronchospasms. Therefore, atropine should be within immediate reach when this therapy is used.

Treatment of collagenous colitis is often challenging. Typically, one or more of the following therapeutic agents are used:

- Bismuth agents, including Pepto-Bismol

- 5-aminosalicylic acid

- Budesonide

- Immunosuppressants, including azathioprine

- Corticosteroids

Pilot-scale studies have shown some evidence of possible benefit for both "Boswellia serrata" extract and specific strains of probiotics in the treatment of collagenous colitis, although larger sample sizes are needed to confirm the results.

The prognosis depends on prompt diagnosis (less than 12–24 hours and before gangrene) and the underlying cause:

- venous thrombosis: 32% mortality

- arterial embolism: 54% mortality

- arterial thrombosis: 77% mortality

- non-occlusive ischemia: 73% mortality.

In the case of prompt diagnosis and therapy, acute mesenteric ischemia can be reversible.

Traditionally, nothing by mouth was considered to be mandatory in all cases, but gentle feeding by enteral feeding tube may help to restore motility by triggering the gut's normal feedback signals, so this is the recommended management initially. When the patient has severe, persistent signs that motility is completely disrupted, nasogastric suction and parenteral nutrition may be required until passage is restored. In such cases, continuing aggressive enteral feeding causes a risk of perforating the gut.

Several options are available in the case of paralytic ileus. Most treatment is supportive. If caused by medication, the offending agent is discontinued or reduced. Bowel movements may be stimulated by prescribing lactulose, erythromycin or, in severe cases that are thought to have a neurological component (such as Ogilvie's syndrome), neostigmine. There is also evidence from a systematic review of randomized controlled trials that chewing gum, as a form of 'sham feeding', may stimulate gastrointestinal motility in the post-operative period and reduce the duration of postoperative ileus.

If possible the underlying cause is corrected (e.g. replace electrolytes).

Possible treatments include:

- In stable cases, use of laxatives and bulking agents, as well as modifications in diet and stool habits are effective.

- Corticosteroids and other anti-inflammatory medication is used in toxic megacolon.

- Antibiotics are used for bacterial infections such as oral vancomycin for "Clostridium difficile"

- Disimpaction of feces and decompression using anorectal and nasogastric tubes.

- When megacolon worsens and the conservative measures fail to restore transit, surgery may be necessary.

- Bethanechol can also be used to treat megacolon by means of its direct cholinergic action and its stimulation of muscarinic receptors which bring about a parasympathetic like effect.

There are several surgical approaches to treat megacolon, such as a colectomy (removal of the entire colon) with ileorectal anastomosis (ligation of the remaining ileum and rectum segments), or a total proctocolectomy (removal of colon, sigmoid and rectum) followed by ileostomy or followed by ileoanal anastomosis.

Budesonide, in colonic release preparations, has been shown in randomized controlled trials to be effective in treating this disorder. It helps control the diarrheal symptoms and treatment is usually given for several weeks. Sometimes it is used to prevent frequent relapses.

Over-the-counter antidiarrheal drugs may be effective for some people with lymphocytic colitis. Anti-inflammatory drugs, such as salicylates, mesalazine, and systemic corticosteroids may be prescribed for people who do not respond to other drug treatment. The long-term prognosis for this disease is good with a proportion of people suffering relapses which respond to treatment.

The exact incidence of ischemic colitis is difficult to estimate, as many patients with mild ischemia may not seek medical attention. Ischemic colitis is responsible for about 1 in 2000 hospital admissions, and is seen on about 1 in 100 endoscopies. Men and women are affected equally; ischemic colitis is a disease of the elderly, with more than 90% of cases occurring in people over the age of 60.

The prognosis for lymphocytic colitis and collagenous colitis is good, and both conditions are considered to be benign. The majority of people afflicted with the conditions recover from their diarrhea, and their histological abnormalities resolve, although relapses commonly occur if maintenance treatment is not continued.

Treatment for colitis-X usually does not save the horse. The prognosis is average to poor, and mortality is 90% to 100%. However, treatments are available, and one famous horse that survived colitis-X was U.S. Triple Crown winner Seattle Slew, that survived colitis-X in 1978 and went on to race as a four-year-old.

Large amounts of intravenous fluids are needed to counter the severe dehydration, and electrolyte replacement is often necessary. Flunixin meglumine (Banamine) may help block the effects of toxemia. Mortality rate has been theorized to fall to 75% if treatment is prompt and aggressive, including administration of not only fluids and electrolytes, but also blood plasma, anti-inflammatory and analgesic drugs, and antibiotics. Preventing dehydration is extremely important. Nutrition is also important. Either parenteral or normal feeding can be used to support the stressed metabolism of the sick horse. Finally, the use of probiotics is considered beneficial in the restoration of the normal intestinal flora. The probiotics most often used for this purpose contain "Lactobacillus" and "Bifidobacterium".

Early treatment is essential to keep the affected limb viable. The treatment options include injection of an anticoagulant, thrombolysis, embolectomy, surgical revascularisation, or amputation. Anticoagulant therapy is initiated to prevent further enlargement of the thrombus. Continuous IV unfractionated heparin has been the traditional agent of choice.

If the condition of the ischemic limb is stabilized with anticoagulation, recently formed emboli may be treated with catheter-directed thrombolysis using intraarterial infusion of a thrombolytic agent (e.g., recombinant tissue plasminogen activator (tPA), streptokinase, or urokinase). A percutaneous catheter inserted into the femoral artery and threaded to the site of the clot is used to infuse the drug. Unlike anticoagulants, thrombolytic agents work directly to resolve the clot over a period of 24 to 48 hours.

Direct arteriotomy may be necessary to remove the clot. Surgical revascularization may be used in the setting of trauma (e.g., laceration of the artery). Amputation is reserved for cases where limb salvage is not possible. If the patient continues to have a risk of further embolization from some persistent source, such as chronic atrial fibrillation, treatment includes long-term oral anticoagulation to prevent further acute arterial ischemic episodes.

Decrease in body temperature reduces the aerobic metabolic rate of the affected cells, reducing the immediate effects of hypoxia. Reduction of body temperature also reduces the inflammation response and reperfusion injury. For frostbite injuries, limiting thawing and warming of tissues until warmer temperatures can be sustained may reduce reperfusion injury.

In the management of small bowel obstructions, a commonly quoted surgical aphorism is: "never let the sun rise or set on small-bowel obstruction" because about 5.5% of small bowel obstructions are ultimately fatal if treatment is delayed. However improvements in radiological imaging of small bowel obstructions allow for confident distinction between simple obstructions, that can be treated conservatively, and obstructions that are surgical emergencies (volvulus, closed-loop obstructions, ischemic bowel, incarcerated hernias, etc.).

A small flexible tube (nasogastric tube) may be inserted through the nose into the stomach to help decompress the dilated bowel. This tube is uncomfortable but does relieve the abdominal cramps, distention, and vomiting. Intravenous therapy is utilized and the urine output is monitored with a catheter in the bladder.

Most people with SBO are initially managed conservatively because in many cases, the bowel will open up. Some adhesions loosen up and the obstruction resolves. However, when conservative management is undertaken, the patient is examined several times a day, and X-ray images are obtained to ensure that the individual is not getting clinically worse.

Conservative treatment involves insertion of a nasogastric tube, correction of dehydration and electrolyte abnormalities. Opioid pain relievers may be used for patients with severe pain. Antiemetics may be administered if the patient is vomiting. Adhesive obstructions often settle without surgery. If the obstruction is complete a surgery is usually required.

Most patients do improve with conservative care in 2–5 days. However, on some occasions, the cause of obstruction may be a cancer and in such cases, surgery is the only treatment. These individuals undergo surgery where the cause of SBO is removed. Individuals who have bowel resection or lysis of adhesions usually stay in the hospital a few more days until they are able to eat and walk.

Small bowel obstruction caused by Crohn's disease, peritoneal carcinomatosis, sclerosing peritonitis, radiation enteritis, and postpartum bowel obstruction are typically treated conservatively, i.e. without surgery.

Some causes of bowel obstruction may resolve spontaneously; many require operative treatment. In adults, frequently the surgical intervention and the treatment of the causative lesion are required. In malignant large bowel obstruction, endoscopically placed self-expanding metal stents may be used to temporarily relieve the obstruction as a bridge to surgery, or as palliation. Diagnosis of the type of bowel obstruction is normally conducted through initial plain radiograph of the abdomen, luminal contrast studies, computed tomography scan, or ultrasonography prior to determining the best type of treatment.

The condition is not usually immediately life-threatening. The intussusception can be treated with either a barium or water-soluble contrast enema or an air-contrast enema, which both confirms the diagnosis of intussusception, and in most cases successfully reduces it. The success rate is over 80%. However, approximately 5–10% of these recur within 24 hours.

Cases where it cannot be reduced by an enema or the intestine is damaged require surgical reduction. In a surgical reduction, the surgeon opens the abdomen and manually squeezes (rather than pulls) the part that has telescoped. If the surgeon cannot successfully reduce it, or the bowel is damaged, they resect the affected section. More often, the intussusception can be reduced by laparoscopy, pulling the segments of intestine apart with forceps.

Aggressive risk factor modification is required for effective treatment of microvascular angina where exercise plays a major role. Several other treatment strategies including b-blockers, angiotensin-converting enzyme inhibitors, ranolazine, l-arginine, statin drugs and potentially estrogen replacement therapy have been shown to relieve anginal symptoms as well as improve vascular function. Nitrates may be effective for symptom relief. Further studies are required to determine whether specific treatments are associated with improved survival as well as decreased symptoms.

Cilostazol or pentoxifylline can improve symptoms in some. Cilostazol may improve walking distance for people who experience claudication due to peripheral artery disease, but there is no strong evidence to suggest that it improves the quality of life, decreases mortality, or decreases the risk of cardiovascular events.

Treatment with other drugs or vitamins are unsupported by clinical evidence, "but trials evaluating the effect of folate and vitamin B-12 on hyperhomocysteinemia, a putative vascular risk factor, are near completion".

Treatment for sigmoid volvulus may include sigmoidoscopy. If the mucosa of the sigmoid looks normal and pink, place a rectal tube for decompression, correct any fluid, electrolyte, cardiac, renal or pulmonary abnormalities and then take the person to the operating room for repair. If surgery is not performed, there is a high rate of recurrence.

For people with signs of sepsis or an abdominal catastrophe, immediate surgery and resection is advised.