Getting rid of "H. pylori" in those who are infected decreases the risk of stomach cancer, at least in those who are Asian. A 2014 meta-analysis of observational studies found that a diet high in fruits, mushrooms, garlic, soybeans, and green onions was associated with a lower risk of stomach cancer in the Korean population. Low doses of vitamins, especially from a healthy diet, decrease the risk of stomach cancer. A previous review of antioxidant supplementation did not find supporting evidence and possibly worse outcomes.

Little research is conducted on these cancers due to their relative rarity when compared to the more common colorectal cancers. APC-min mice which carry a gene deficiency corresponding to that of humans with FAP also go on to develop small intestinal tumors, though humans do not.

The stomach is a muscular organ of the gastrointestinal tract that holds food and begins the digestive process by secreting gastric juice. The most common cancers of the stomach are adenocarcinomas but other histological types have been reported. Signs vary but may include vomiting (especially if blood is present), weight loss, anemia, and lack of appetite. Bowel movements may be dark and tarry in nature. In order to determine whether cancer is present in the stomach, special X-rays and/or abdominal ultrasound may be performed. Gastroscopy, a test using an instrument called endoscope to examine the stomach, is a useful diagnostic tool that can also take samples of the suspected mass for histopathological analysis to confirm or rule out cancer. The most definitive method of cancer diagnosis is through open surgical biopsy. Most stomach tumors are malignant with evidence of spread to lymph nodes or liver, making treatment difficult. Except for lymphoma, surgery is the most frequent treatment option for stomach cancers but it is associated with significant risks.

In most people with peptic ulcer disease, the oedema will usually settle with conservative management with nasogastric suction, replacement of fluids and electrolytes and proton pump inhibitors.

The treatment for bile reflux is the same as the treatment for acidic reflux. In general, everything that can

reduce acidic reflux can reduce bile reflux. Examples include lifestyle modification, weight reduction, and the avoidance of eating immediately before sleep or being in the supine position immediately after meals. In addition, smoking has been found to be a factor in the development of acidic reflux. Thus, all of these factors should be applied to bile reflux as well.

Likewise, drugs that reduce the secretion of gastric acid (e.g., proton pump inhibitors)

or that reduce gastric contents or volume can be used to treat acidic bile reflux. Because prokinetic drugs increase the motility of the stomach and accelerate gastric emptying, they can also reduce bile reflux. Other drugs that reduce the relaxations of the lower esophageal sphincter, such as baclofen, have also proven to reduce bile reflux, particularly in patients who are refractory to (medically unresponsive to) proton pump inhibitor therapy.

Medications used in managing biliary reflux include bile acid sequestrants, particularly cholestyramine, which disrupt the circulation of bile in the digestive tract and sequester bile that would otherwise cause symptoms when refluxed; and prokinetic agents, to move material from the stomach to the small bowel more rapidly and prevent reflux.

Biliary reflux may also be treated surgically, if medications are ineffective or if precancerous tissue is present in the esophagus.

Treatment of gastric outlet obstruction depends on the cause, but is usually either surgical or medical.

Risk factors for small intestine cancer include:

- Crohn's disease

- Celiac disease

- Radiation exposure

- Hereditary gastrointestinal cancer syndromes: familial adenomatous polyposis, hereditary nonpolyposis colorectal cancer, Peutz-Jeghers syndrome

- Males are 25% more likely to develop the disease

Benign tumours and conditions that may be mistaken for cancer of the small bowel:

- Hamartoma

- Tuberculosis

Perforated peptic ulcer is a surgical emergency and requires surgical repair of the perforation. Most bleeding ulcers require endoscopy urgently to stop bleeding with cautery, injection, or clipping.

Cancer of the stomach, also called gastric cancer, is the fourth-most-common type of cancer and the second-highest cause of cancer death globally. Eastern Asia (China, Japan, Korea, Mongolia) is a high-risk area for gastric cancer, and North America, Australia, New Zealand and western and northern Africa are areas with low risk. The most common type of gastric cancer is adenocarcinoma, which causes about 750,000 deaths each year. Important factors that may contribute to the development of gastric cancer include diet, smoking and alcohol consumption, genetic aspects (including a number of heritable syndromes) and infections (for example, "Helicobacter pylori" or Epstein-Barr virus) and pernicious anemia. Chemotherapy improves survival compared to best supportive care, however the optimal regimen is unclear.

Gastrointestinal cancer refers to malignant conditions of the gastrointestinal tract (GI tract) and accessory organs of digestion, including the esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum and anus. The symptoms relate to the organ affected and can include obstruction (leading to difficulty swallowing or defecating), abnormal bleeding or other associated problems. The diagnosis often requires endoscopy, followed by biopsy of suspicious tissue. The treatment depends on the location of the tumor, as well as the type of cancer cell and whether it has invaded other tissues or spread elsewhere. These factors also determine the prognosis.

Overall, the GI tract and the accessory organs of digestion (pancreas, liver, gall bladder) are responsible for more cancers and more deaths from cancer than any other system in the body. There is significant geographic variation in the rates of different gastrointestinal cancers.

H2 antagonists or proton-pump inhibitors decrease the amount of acid in the stomach, helping with healing of ulcers.

Since many, if not most, anal cancers derive from HPV infections, and since the HPV vaccine before exposure to HPV prevents infection by some strains of the virus and has been shown to reduce the incidence of potentially precancerous lesions, scientists surmise that HPV vaccination may reduce the incidence of anal cancer.

On 22 December 2010, the U.S. Food and Drug Administration approved Gardasil vaccine to prevent anal cancer and pre-cancerous lesions in males and females aged 9 to 26 years. The vaccine has been used before to help prevent cervical, vulvar, and vaginal cancer, and associated lesions caused by HPV types 6, 11, 16, and 18 in women.

Antacids are a common treatment for mild to medium gastritis. When antacids do not provide enough relief, medications such as H blockers and proton-pump inhibitors that help reduce the amount of acid are often prescribed.

Cytoprotective agents are designed to help protect the tissues that line the stomach and small intestine. They include the medications sucralfate and misoprostol. If NSAIDs are being taken regularly, one of these medications to protect the stomach may also be taken. Another cytoprotective agent is bismuth subsalicylate.

Several regimens are used to treat "H. pylori" infection. Most use a combination of two antibiotics and a proton pump inhibitor. Sometimes bismuth is added to the regimen.

Current dietary recommendations to prevent colorectal cancer include increasing the consumption of whole grains, fruits and vegetables, and reducing the intake of red meat and processed meats. Higher physical activity is also recommended. Physical exercise is associated with a modest reduction in colon but not rectal cancer risk. High levels of physical activity reduce the risk of colon cancer by about 21%. Sitting regularly for prolonged periods is associated with higher mortality from colon cancer. The risk is not negated by regular exercise, though it is lowered. The evidence for any protective effect conferred by fiber and fruits and vegetables is, however, poor. The risk of colon cancer can be reduced by maintaining a normal body weight.

Greater than 75–95% of colorectal cancer occurs in people with little or no genetic risk. Risk factors include older age, male gender, high intake of fat, alcohol, red meat, processed meats, obesity, smoking, and a lack of physical exercise. Approximately 10% of cases are linked to insufficient activity. The risk from alcohol appears to increase at greater than one drink per day. Drinking 5 glasses of water a day is linked to a decrease in the risk of colorectal cancer and adenomatous polyps. "Streptococcus gallolyticus" is associated with colorectal cancer. Some strains of "Streptococcus bovis/Streptococcus equinus" complex are consumed by millions of people daily and thus may be safe. 25 to 80% of people with "Streptococcus bovis/gallolyticus" bacteremia have concomitant colorectal tumors. Seroprevalence of "Streptococcus bovis/gallolyticus" is considered as a candidate practical marker for the early prediction of an underlying bowel lesion at high risk population. It has been suggested that the presence of antibodies to "Streptococcus bovis/gallolyticus" antigens or the antigens themselves in the bloodstream may act as markers for the carcinogenesis in the colon.

10 to 20% of patients treated for anal cancer will develop distant metastatic disease following treatment. Metastatic or recurrent anal cancer is difficult to treat, and usually requires chemotherapy. Radiation is also employed to palliate specific locations of disease that may be causing symptoms. Chemotherapy commonly used is similar to other squamous cell epithelial neoplasms, such as platinum analogues, anthracyclines such as doxorubicin, and antimetabolites such as 5-FU and capecitabine. JD Hainsworth developed a protocol that includes Taxol and Carboplatinum along with 5-FU. Median survival rates for patients with distant metastases ranges from 8 to 34 months.

The need for medications to prevent stress ulcer among those in the intensive care unit is unclear. As of 2014, the quality of the evidence is poor. It is unclear which agent is best or if prevention is needed at all. Benefit may only occur in those who are not being fed.

Possible agents include antacids, H2-receptor blockers, sucralfate, and proton pump inhibitors (PPIs). Tentative evidence supports that PPIs may be better than H2 blockers.

Concerns with the use of stress ulcer prophylaxis agents include increased rates of pneumonia and "Clostridium difficile" colitis.

Early treatment includes removing fluids from the stomach via a nasogastric tube, and providing fluids intravenously. The definitive treatment for duodenal atresia is surgery (duodenoduodenostomy), which may be performed openly or laparoscopically. The surgery is not urgent. The initial repair has a 5 percent morbidity and mortality rate.

A transjugular intrahepatic portosystemic shunt (TIPS or TIPSS) procedure is used to treat portal hypertension when that is present as an associated condition. Unfortunately, the TIPSS, which has been used for similar conditions, may cause or exacerbate hepatic encephalopathy. TIPSS-related encephalopathy occurs in about 30% of cases, with the risk being higher in those with previous episodes of encephalopathy, higher age, female sex, and liver disease due to causes other than alcohol. The patient, with his or her physician and family, must balance out a reduction in bleeding caused by TIPS with the significant risk of encephalopathy. Various shunts have been shown in a meta-study of 22 studies to be effective treatment to reduce bleeding, yet none have any demonstrated survival advantage.

If there is cirrhosis of the liver that has progressed to liver failure, then lactulose may be prescribed for hepatic encephalopathy, especially for "Type C encephalopathy" with diabetes. Also, "antibiotics such as neomycin, metronidazole, and rifaximin" may be used effectively to treat the encephalopathy by removing nitrogen-producing bacteria from the gut.

Paracentesis, a medical procedure involving needle drainage of fluid from a body cavity, may be used to remove fluid from the peritoneal cavity in the abdomen for such cases. This procedure uses a large needle, similar to the better-known amniocentesis.

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

Among those in the intensive care unit, ulceration resulting in bleeding is very rare.

treatment to be directed towards the findings in investigation if it is found to be AMAG immunosupressive drugs and chemotherapy with antineoplastic drugs.

In case of confirmed malignancy of stomach complete or step ladder or stage ladder resection of gastric or stomach to be done.

A number of endoscopic devices have been tested to treat chronic heartburn.

- Endocinch, puts stitches in the lower esophogeal sphincter (LES) to create small pleats to help strengthen the muscle. However, long-term results were disappointing, and the device is no longer sold by Bard.

- Stretta procedure, uses electrodes to apply radio-frequency energy to the LES. A 2015 systematic review and meta-analysis in response to the systematic review (no meta-analysis) conducted by SAGES did not support the claims that Stretta was an effective treatment for GERD. A 2012 systematic review found that it improves GERD symptoms.

- NDO Surgical Plicator creates a plication, or fold, of tissue near the gastroesophageal junction, and fixates the plication with a suture-based implant. The company ceased operations in mid-2008, and the device is no longer on the market.

- Transoral incisionless fundoplication, which uses a device called Esophyx, may be effective.

Evidence does not support a role for specific foods including spicy foods and coffee in the development of peptic ulcers. People are usually advised to avoid foods that bother them.

Certain foods and lifestyle are considered to promote gastroesophageal reflux, but most dietary interventions have little supporting evidence. Avoidance of specific foods and of eating before lying down should be recommended only to those in which they are associated with the symptoms. Foods that have been implicated include coffee, alcohol, chocolate, fatty foods, acidic foods, and spicy foods. Weight loss and elevating the head of the bed are generally useful. A wedge pillow that elevates the head may inhibit gastroesophageal reflux during sleep. Stopping smoking and not drinking alcohol do not appear to result in significant improvement in symptoms. Although moderate exercise may improve symptoms in people with GERD, vigorous exercise may worsen them.