Question: What are the symptoms of ulcerative colitis?
Answer: Symptoms of ulcerative colitis vary from person to person. Common symptoms of ulcerative colitis include

diarrhea
passing blood with yourstoolorrectal bleeding
cramping and pain in theabdomen
passingmucusorpuswith your stool
tenesmus, which means feeling a constant urge to have a bowel movement even though your bowel may be empty
an urgent need to have abowel movement

Symptoms of ulcerative colitis may vary in severity. For example, mild symptoms may include having fewer than four bowel movements a day and sometimes passing blood with stool. Severe symptoms may include having more than six bowel movements a day and passing blood with stool most of the time. In extremely severe—or fulminant—ulcerative colitis, you may have more than 10 bloody bowel movements in a day.3,4

Some symptoms are more likely to occur if ulcerative colitis is more severe or affects more of the large intestine. These symptoms include

fatigue, or feeling tired
fever
nauseaorvomiting
weight loss

You may have periods of remission—times when symptoms disappear—that can last for weeks or years. After a period of remission, you may have a relapse, or a return of symptoms.
Question: What causes ulcerative colitis?
Answer: Doctors aren’t sure what causes ulcerative colitis. Experts think that the following factors may play a role in causing ulcerative colitis.

Genes

Ulcerative colitis sometimes runs in families. Research suggests that certain genes increase the chance that a person will develop ulcerative colitis.

Abnormal immune reactions

Abnormal reactions of the immune system may play a role in causing ulcerative colitis. Abnormal immune reactions lead to inflammation in the large intestine.

Microbiome

The microbes in your digestive tract—including bacteria, viruses, and fungi—that help with digestion are called the microbiome. Studies have found differences between the microbiomes of people who have IBD and those who don’t. Researchers are still studying the relationship between the microbiome and IBD.

Environment

Experts think a person’s environment—one’s surroundings and factors outside the body—may play a role in causing ulcerative colitis. Researchers are still studying how people’s environments interact with genes, the immune system, and the microbiome to affect the chance of developing ulcerative colitis.