Lower Gastrointestinal (GI) Tract Conditions

Part of: Gut Health

Common lower gastrointestinal (GI) tract conditions

The lower gastrointestinal (GI) tract plays the important role of:

  • Absorbing nutrients from what you consume
  • Expelling waste products from your body

It starts from the midsection of the small intestine and includes the large intestine and anus. In the small intestine, food digested by the stomach continues to break down until its nutrients can be absorbed easily. In the large intestine, waste products are turned into stools. The rectum holds the stool until it is ready to leave the body through the anus.

Disorders in the lower digestive tract can lead to discomfort in the stomach and serious complications. They usually require prompt clinical care by a gastroenterologist.

Learn to spot lower GI conditions and explore gastroenterology treatments and services.

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Colorectal cancer is also known as large bowel cancer. If the cancer affects the:

  • Colon (the longest part of the large intestine), the cancer is known as colon cancer.
  • Rectum (the last several inches of the large intestine before the anus), the cancer is known as rectal cancer.

As most symptoms do not appear until the cancer has advanced, it is important to undergo regular colorectal cancer screening. Depending on the cancer's location, how advanced it is, and how it affects nearby organs and tissue, signs and symptoms may include:

  • Feeling very tired all the time
  • Feeling full or bloated very easily
  • Feeling that your bowel does not empty completely
  • Finding your stools are narrower than usual
  • Losing weight with no known reason
  • Passing out blood or blood in stool
  • Frequent tummy pain or cramps
  • Diarrhoea or constipation

Learn more about colorectal cancer and its treatments.

Crohn's disease is a chronic (long-term) inflammatory disease that primarily affects the small and large intestines. The disease results in the inflammation of the digestive tract, which can cause:

  • Diarrhoea
  • Abdominal pain
  • Blood in stool
  • Malnutrition
  • Weight loss
  • Fatigue

The inflammation can involve different areas of the digestive tract, and often spreads deep into the layers of affected bowel tissues. Crohn's disease can be painful and debilitating, and may lead to serious complications.

Irritable bowel syndrome (IBS) is a common condition affecting how the digestive tract senses or responds to food, drinks or gas. It can cause:

  • Gas and bloating
  • Pain and discomfort
  • Changes in bowel habits (constipation or diarrhoea)

Learn more about IBS and its treatment options.

Diverticular disease occurs when small pockets or bulges develop within the lining of the large intestine. Diverticulosis refers to the development of small pockets, whereas diverticulitis refers to the inflammation of these small pockets.

This disease may cause lower abdominal pain, and is usually associated with:

  • Ageing
  • Inadequate fibre intake
  • Constipation

Learn more about diverticular disease and its treatment options.

Polyps are abnormal growths. In the lower GI tract, they usually form on the lining of the colon (large intestine). Whilst most polyps are non-cancerous, certain types may eventually develop into cancer.

Most polyps do not cause any symptoms unless they grow to a certain size, which is why regular screening is important. Colon polyps can cause:

  • Abdominal pain
  • Blood in the stools, which may indicate bleeding in the colon.
  • Changes in bowel habits such as constipation or diarrhoea that lasts longer than a week.
  • Fatigue, shortness of breath, or anaemia, which are indications of chronic bleeding.

Ulcerative colitis is a type of inflammatory bowel disease. It affects the innermost lining of the large intestine (colon) and rectum.

Patients with this condition have:

  • Chronic inflammation of the colon
  • Ulcers that gradually worsen, and can bleed and produce pus

Learn more about ulcerative colitis and its treatment options.

Haemorrhoids occur when veins around the anus or lower rectum become swollen or inflamed. It is also known as piles.

Symptoms of piles include:

  • Itch or pain at the anus
  • Bleeding during bowel movements

Depending on your condition, there is a range of treatment options. For severe haemorrhoids, pile ligation or surgery may be required.

Learn more about haemorrhoids and its treatment options.

This page has been reviewed by our medical content reviewers.