Ulcerative colitis (UC) involves inflammation of the lining of the large intestine. People with UC tend to experience pain in the left side of the abdomen or in the rectum. The severity and frequency of pain vary depending on the extent of the inflammation.

UC is one of the most common forms of inflammatory bowel disease (IBD). Inflammation results in the formation of tiny sores called ulcers on the inner lining of the colon.

These ulcers may lead to bleeding and the discharge of pus. A person with UC might experience abdominal pain and diarrhea, and they might notice blood in their stool.

The specific location of pain varies depending on the type of UC a person has and the extent of inflammation in the colon. However, UC tends to affect the left side of the abdomen, whereas Crohn’s disease, another common type of IBD, typically affects the right side.

In this article, we discuss the symptoms of UC, including the most likely sites of pain. We also look at the causes, diagnosis, and treatment of the condition.

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UC is one of the most common types of IBD, with an incidence of 9–20 cases per 100,000 people per year. It is most prevalent in North America and Northern Europe and is more likely to affect adults than children.

Risk factors

The risk factors for developing UC include:

  • Age: UC can occur at any age, but it is more common among people aged 15–30 years.
  • Ethnicity: People of Jewish descent have a higher risk of UC.
  • Family history: People who have a parent, sibling, or child with UC are more likely to develop the condition.


The exact cause of UC is still unclear. However, a few factors that may contribute to its development include:

Visit our IBD hub to learn more about UC and similar conditions.

Pain is a common symptom of UC. According to the Crohn’s & Colitis Foundation, 33% of people with UC experience chronic abdominal pain. Pain management is, therefore, an important part of the treatment plan.

Pain due to UC occurs most commonly in two regions: the rectum and the lower left side of the abdomen. Doctors associate the areas of inflammation with a certain type of UC.

The severity of the symptoms can vary over time, with people often experiencing periods of mild or no symptoms, known as remission, alternating with periods of more severe symptoms, known as flare-ups.

Rectal pain

Gastroenterologists associate rectal pain with proctitis. Proctitis generally refers to acute rectal inflammation or chronic inflammation.

Some of the common symptoms of ulcerative proctitis include:

  • a constant urge to pass stools
  • diarrhea or constipation
  • cramping or pain in the rectum or to the left of the abdomen while having a bowel movement
  • the passing of blood in the stool
  • stools with mucus

Left-sided pain

Whether a person experiences pain in the left side of the abdomen depends on the type of UC. This symptom may occur with left-sided colitis and proctosigmoiditis.

In people with left-sided colitis, the inflammation begins in the rectum and extends into the colon as far as the bend by the spleen. This results in pain on the left side of the abdomen.

Proctosigmoiditis is similar to left-sided UC, but it affects the rectum and the lower part of the colon, known as the sigmoid colon.

Proctosigmoiditis causes symptoms that are similar to those of left-sided UC, including:

  • bloody stool
  • diarrhea
  • loss of appetite
  • unexplained weight loss

Learn more about the different types of UC.

Vs. Crohn’s

The pain location of another common form of IBD, Crohn’s disease, differs from UC. People with Crohn’s disease tend to experience pain in the lower right part of the abdomen.

Learn more about the differences between Crohn’s disease and UC.

Musculoskeletal symptoms can occur in people with UC. Pain can be present on both sides of the body, above and below the waist, and in the axial area, meaning the chest, the neck, and the middle and lower spine.

In a 2020 study, people with UC reported more chronic pain in their lower back and hip region compared with the general population. Higher UC disease activity correlated with more pain in all affected body regions.

Chronic UC can affect the peripheral joints and the axial skeleton, leading to pain in other parts of the body. These might include the:

  • knee
  • ankle
  • lower leg
  • foot

The location of pain will determine the tests that doctors use to diagnose UC. The options include:

  • Colonoscopy: A doctor uses a colonoscopy, which is a type of endoscopy, to view the lining of the rectum and the entire colon. This procedure can help them diagnose all types of UC based on the area of inflammation.
  • Flexible sigmoidoscopy: This type of endoscopy is particularly useful in the diagnosis of proctosigmoiditis. It allows doctors to examine the lower rectum and sigmoid colon.

Other diagnostic tests

Other tests that doctors may use to aid a diagnosis include:

  • Blood tests: Blood tests can be useful to check for signs of UC and other complications. They can help a doctor identify any signs of anemia or inflammation.
  • Stool tests: Doctors use these to check for signs of inflammation that can be indicative of UC or an infection.
  • Biopsy: This procedure involves the analysis of a small portion of tissue from the lining of the rectum and colon.

Learn more about the diagnosis of UC.

There are various treatment options for UC, and the best approach for a person will depend on the severity of their symptoms. Over-the-counter (OTC) medications can sometimes help relieve the pain that UC can cause. However, severe cases require stronger pain relievers.

Medications for the treatment of UC include:


These are anti-inflammatory compounds containing 5-aminosalicylic acid (5-ASA). An example is mesalamine (Lialda), which helps decrease inflammation, reduce symptoms, and maintain remission.

Doctors will prescribe 5-ASA via an enema or in oral form for people with left-sided inflammation.


Corticosteroids help keep the immune system in check and prevent short-term flare-ups. Examples include budesonide (Uceris) and prednisone (Rayos).

Biologic therapies

Biologics may be a good option for people who do not respond to conventional therapies. Four common biologics are golimumab (Simponi), adalimumab (Humira), infliximab (Remicade), and certolizumab (Cimzia).

Doctors may prescribe any of these types of medication for proctitis and moderate cases of left-sided colitis. In more severe cases, a combination of medication types may be necessary.

People who experience certain complications or do not respond to medications may need to undergo surgery.

Learn more about the treatments for UC.

Natural remedies

Some people may also find natural remedies helpful in treating and preventing UC. The options include:

  • Probiotics: The intestines and stomach are home to a significant number of good bacteria that keep harmful bacteria in check. Any imbalance between the two can result in diarrhea and other digestive problems. Probiotics aim to help restore the good bacteria, and they are unlikely to lead to any side effects in people with a good health status.
  • Aloe vera: People worldwide use this tropical medicinal plant. Aloe vera juice has anti-inflammatory properties and may help treat UC.
  • Curcumin: This is a chemical present in turmeric. It originates from ginger root and can help reduce inflammation.
  • Omega-3 fatty acids: These supplements can help treat UC due to their anti-inflammatory properties.

Learn more about other natural remedies for UC.

Dietary changes

A person can also adjust their diet to try to avoid foods that may result in a UC flare-up. Adjustments that may help include:

Learn more about what foods to eat and avoid with UC.

Below, we answer some of the questions that people often ask about UC.

What are the first symptoms a person may experience?

The first symptom of UC is often diarrhea, which may begin slowly or suddenly. Along with diarrhea, some people experience abdominal pain and an increased urge to go to the bathroom.

What does the pain feel like?

The intensity of abdominal pain varies among individuals. The abdominal pain feels like a sensation of squeezing and releasing, which people may refer to as cramping. Other parts of the body might hurt, as well.

How long does UC pain last?

Anecdotal evidence suggests that UC pain can last for between a few days and a few weeks. Following this is the remission period, which tends to last at least a few months and can be as long as a few years.

Does UC hurt all the time?

UC occurs during flare-ups and should be absent or mild during periods of remission. The extent of the pain and the duration and frequency of flare-ups will depend on the severity of the disease.

Ulcerative colitis is a type of IBD. The symptoms can vary depending on the severity of the disease. The pain location helps doctors diagnose UC and determine the type.

Pain in the left side of the abdomen and rectal pain are typically indicative of UC. OTC medications can help treat pain in some cases, but prescription-strength pain relievers or surgery may be necessary to alleviate more severe symptoms.

Various medications and natural remedies are available for the treatment of UC. A doctor can advise a person on the best treatment methods for them. A person will need to continue the treatment for the prescribed duration to prevent the relapse of symptoms.