Most cases of simple, uncomplicated diverticulitis respond to conservative therapy with bowel rest.

If bacterial infection is suspected, antibiotics may be used. Despite being recommended by several guidelines, the use of antibiotics in mild cases of uncomplicated diverticulitis is supported with only "sparse and of low quality" evidence, with no evidence supporting their routine use.

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.

A high-fiber diet and fiber supplements are advisable to prevent constipation. The American Dietetic Association recommends 20–35 grams each day. Wheat bran has been shown to reduce intra colonic pressure.

The US National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) says foods such as nuts, popcorn hulls, sunflower seeds, pumpkin seeds, caraway seeds, and sesame seeds have traditionally been labeled as problem foods for people with this condition; however, no scientific data exists to prove this hypothesis. The seeds in tomatoes, zucchini, cucumbers, strawberries, raspberries, and poppy seeds, are not considered harmful by the NIDDK.

One study found that nuts and popcorn do not contribute positively or negatively to patients with diverticulosis or diverticular complications.

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.

Surgical intervention is nearly always required in form of exploratory laparotomy and closure of perforation with peritoneal wash. Occasionally they may be managed laparoscopically.

Conservative treatment including intravenous fluids, antibiotics, nasogastric aspiration and bowel rest is indicated only if the person is nontoxic and clinically stable.

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.

Acute appendicitis is typically managed by surgery. However, in uncomplicated cases, antibiotics are effective and safe. While antibiotics are effective for treating uncomplicated appendicitis, 26% of people had a recurrence within a year and required eventual appendectomy. They work less well if an appendicolith is present. Cost effectiveness of surgery versus antibiotics is unclear.

Distal or sigmoid, fecalomas can often be disimpacted digitally or by a catheter which carries a flow of disimpaction fluid (water or other solvent or lubricant). Surgical intervention in the form of sigmoid colectomy or proctocolectomy and ileostomy may be required only when all conservative measures of evacuation fail.

Pain medications (such as morphine) do not appear to affect the accuracy of the clinical diagnosis of appendicitis and therefore should be given early in the patient's care. Historically there were concerns among some general surgeons that analgesics would affect the clinical exam in children, and some recommended that they not be given until the surgeon was able to examine the person.

Treatment is surgical, potentially with a laparoscopic resection. In patients with bleeding, strangulation of bowel, bowel perforation or bowel obstruction, treatment involves surgical resection of both the Meckel's diverticulum itself along with the adjacent bowel segment, and this procedure is called a "small bowel resection". In patients without any of the aforementioned complications, treatment involves surgical resection of the Meckel's diverticulum only, and this procedure is called a simple diverticulectomy.

With regards to asymptomatic Meckel's diverticulum, some recommend that a search for Meckel's diverticulum should be conducted in every case of appendectomy/laparotomy done for acute abdomen, and if found, Meckel's diverticulectomy or resection should be performed to avoid secondary complications arising from it.

GAVE is treated commonly by means of an endoscope, including argon plasma coagulation and electrocautery. Since endoscopy with argon photocoagulation is "usually effective", surgery is "usually not required". Coagulation therapy is well-tolerated but "tends to induce oozing and bleeding." "Endoscopy with thermal ablation" is favored medical treatment because of its low side effects and low mortality, but is "rarely curative." Treatment of GAVE can be categorized into endoscopic, surgical and pharmacologic. Surgical treatment is definitive but it is rarely done nowadays with the variety of treatment options available. Some of the discussed modalities have been used in GAVE patients with another underlying disease rather than SSc; they are included as they may be tried in resistant SSc-GAVE patients. Symptomatic treatment includes iron supplementation and blood transfusion for cases with severe anemia, proton pump inhibitors may ameliorate the background chronic gastritis and minute erosions that commonly co-existed in biopsy reports.

Other medical treatments have been tried and include estrogen and progesterone therapy, Corticostreoids are effective, but are "limited by their side effects."

Diagnostic measures can be used as interventions to help stop bleeding in some cases. Bleeding that occurs due to a neoplasm (cancer growth) can be treated using colonoscopy and clipping, surgical intervention, or other measures, depending on the form and stage of cancer. Similarly, gastric cancer is treated depending on the staging, although typically requires surgical and medical therapy.

The treatment for motility issues, namely constipation, is typically to improve the movement of waste though the GI tract. This is done by using stool softeners (which work by pulling water into the stool while in the colon), addition of fiber to the diet, and use of osmotic laxatives (which help fluid movement through the colon, improving overall motility). Improving a persons gut motility can reduce the straining during defection and decrease the risk of developing of anal fissures. Anal fissures are associated with pain and blood on the toilet paper, and require time for healing. Treatment includes topical nitrates or calcium channel blockers and surgical interventions for chronic or complex cases. Similar to anal fissures, internal hemorrhoids can cause blood on the tissue when wiping, and be felt at the opening of the anus. Treatment options for hemorrhoids can be dependent on whether an underlying cause exists. An anorectal varices related hemorrhoids caused by cirrhosis, however symptomatic treatment often involves removal.

Colitis can be divided into infectious and drug induced, as can the treatment for these conditions. With infectious colitis, treatment is pathogen dependent, and generally requires the use of antibiotics. With drug-induced colitis, treatment typically involves removal of the offending agent, as is the case in NSAID induced PUD, however, removing radiation from a cancer patient is not always practical within a treatment regimen, so medical treatment is the primary mode of treatment.

Structural compromise leading to blood in stool is caused by a variety of conditions, and therefore requires different treatment for each condition. Peptic ulcer disease alone can be divided into multiple causes, but is generally initially controlled primarily with a proton pump inhibitor, with the addition of an H blocker, or in serious cases, requiring surgical intervention. Diverticulitis and diverticulosis require antibiotic treatment, and may require surgical intervention.

Inflammatory bowel disease is also divided into separate conditions, namely ulcerative colitis and Crohn's disease, which have different medical treatment regimens, and may require surgical intervention in more serious conditions.

In a cecal volvulus, the cecum may be returned to a normal position and sutured in place, a procedure known as cecopexy. If identified early, before presumed intestinal wall ischemia has resulted in tissue breakdown and necrosis, the cecal volvulus can be detorsed laparoscopically.

Depending on the severity of the patient's state, the management of peritonitis may include:

- General supportive measures such as vigorous intravenous rehydration and correction of electrolyte disturbances.

- Antibiotics are usually administered intravenously, but they may also be infused directly into the peritoneum. The empiric choice of broad-spectrum antibiotics often consist of multiple drugs, and should be targeted against the most likely agents, depending on the cause of peritonitis (see above); once one or more agents are actually isolated, therapy will of course be target on them.

- Gram positive and gram negative organisms must be covered. Out of the cephalosporins, cefoxitin and cefotetan can be used to cover gram positive bacteria, gram negative bacteria, and anaerobic bacteria. Beta-lactams with beta lactamase inhibitors can also be used, examples include ampicillin/sulbactam, piperacillin/tazobactam, and ticarcillin/clavulanate. Carbapenems are also an option when treating primary peritonitis as all of the carbapenems cover gram positives, gram negatives, and anaerobes except for ertapenem. The only fluoroquinolone that can be used is moxifloxacin because this is the only fluoroquinolone that covers anaerobes. Finally, tigecycline is a tetracycline that can be used due to its coverage of gram positives and gram negatives. Empiric therapy will often require multiple drugs from different classes.

- Surgery (laparotomy) is needed to perform a full exploration and lavage of the peritoneum, as well as to correct any gross anatomical damage that may have caused peritonitis. The exception is spontaneous bacterial peritonitis, which does not always benefit from surgery and may be treated with antibiotics in the first instance.

Fecal impaction and attempts at removal can have severe and even lethal effects, such as the rupture of the colon wall by catheter or an acute angle of the fecaloma (stercoral perforation), followed by septicemia. A small fecalith is one cause of both appendicitis and acute diverticulitis. It may also lead to stercoral perforation, a condition characterized by bowel perforation due to pressure necrosis from a fecal mass or fecaloma.

If laxatives are used, milk of magnesia or polyethylene glycol are recommended as first-line agents due to their low cost and safety. Stimulants should only be used if this is not effective. In cases of chronic constipation, polyethylene glycol appears superior to lactulose. Prokinetics may be used to improve gastrointestinal motility. A number of new agents have shown positive outcomes in chronic constipation; these include prucalopride and lubiprostone. Cisapride is widely available in third world countries, but has withdrawn in most of the west. It has not been shown to have a benefit on constipation, while potentially causing cardiac arrhythmias and deaths.

Soluble fiber supplements such as psyllium are generally considered first-line treatment for chronic constipation, compared to insoluble fibers such as wheat bran. Side effects of fiber supplements include bloating, flatulence, diarrhea, and possible malabsorption of iron, calcium, and some medications. However, patients with opiate-induced constipation will likely not benefit from fiber supplements.

A Meckel's diverticulum, a true congenital diverticulum, is a slight bulge in the small intestine present at birth and a vestigial remnant of the omphalomesenteric duct (also called the vitelline duct or yolk stalk). It is the most common malformation of the gastrointestinal tract and is present in approximately 2% of the population, with males more frequently experiencing symptoms.

Meckel's diverticulum was first explained by Fabricius Hildanus in the sixteenth century and later named after Johann Friedrich Meckel, who described the embryological origin of this type of diverticulum in 1809.

Diverticular disease is when problems occur due to diverticulosis, a condition defined by the presence of pouches in the wall of the large intestine (diverticula). This includes diverticula becoming inflamed (diverticulitis) or bleeding. Colonic perforation due to diverticular disease may be classified using the Hinchey Classification.

Anemia is a common complication of blood in the stool, especially when there is a large amount of blood or bleeding occurs over a long period of time. Anemia is also commonly associated with an iron deficiency, due to the importance of iron in the formation of red blood cells (RBCs). When anemia is diagnosed as a result of blood in the stool, vitamins that are important for RBC formation (folate, vitamin B12, and vitamin C) are frequently prescribed in order to ensure that all the materials are available for those cells that are made.

Gastrointestinal perforation, also known as ruptured bowel, is a hole in the wall of part of the gastrointestinal tract. The gastrointestinal tract includes the esophagus, stomach, small intestine, and large intestine. Symptoms include severe abdominal pain and tenderness. When the hole is in the stomach or early part of the small intestine the onset of pain is typically sudden while with a hole in the large intestine onset may be more gradual. The pain is usually constant in nature. Sepsis, with an increased heart rate, increased breathing rate, fever, and confusion may occur.

The cause can include trauma such as from a knife wound, eating a sharp object, or a medical procedure such as colonoscopy, bowel obstruction such as from a volvulus, colon cancer, or diverticulitis, stomach ulcers, ischemic bowel, and a number of infections including "C. difficile". A hole allows intestinal contents to enter the abdominal cavity. The entry of bacteria results in a condition known as peritonitis or in the formation of an abscess. A hole in the stomach can also lead to a chemical peritonitis due to gastric acid. A CT scan is typically the preferred method of diagnosis; however, free air from a perforation can often be seen on plain X-ray.

Perforation anywhere along the gastrointestinal tract typically requires emergency surgery in the form of an exploratory laparotomy. This is usually carried out along with intravenous fluids and antibiotics. A number of different antibiotics may be used such as piperacillin/tazobactam or the combination of ciprofloxacin and metronidazole. Occasionally the hole can be sewn closed while other times a bowel resection is required. Even with maximum treatment the risk of death can be as high as 50%. A hole from a stomach ulcer occurs in about 1 per 10,000 people per year, while one from diverticulitis occurs in about 0.4 per 10,000 people per year.

A vesicointestinal fistula (or intestinovesical fistula) is a form of fistula between the bladder and the bowel.