Poop irregularities may be more “regular” than you think.
In a new Health survey of 2,001 adults in the U.S., a third of respondents reported poop abnormalities in the past month, such as seeing blood, mucus, or undigested food in their stool.
Rachel Issaka, MD, MAS, a board-certified gastroenterologist at the Fred Hutchinson Cancer Center and University of Washington Medical Center, told Health that these results don’t surprise her, given how common gastrointestinal (GI) symptoms are.
What she did find concerning, however, is that many respondents reported hesitating to seek medical treatment for symptoms that could be serious.
“It is possible that a doctor will provide reassurance that the bowel changes are normal for that individual based on their history,” Issaka said. “But if there is a more serious cause, like colorectal cancer, patients do much better when they are diagnosed as early as possible.”
While 62% of Health survey respondents said they have normal bowel movements, a relatively high number (34%) experienced at least one abnormality in the last month, including:
- Blood in their stool or on toilet paper (11%)
- Mucus (10%)
- Undigested food (14%)
- Unusual color (11%)
- Unusual shape (14%)
There were stark generational differences in these results. About half of millennials (51%) and Gen Z (48%) had at least one of these abnormalities, compared with 34% of Gen X and just 15% of boomers.
Health.com / Datawrapper
Issaka said this may be a matter of heightened awareness. Bowel health is increasingly on younger adults’ minds, she noted, as several younger celebrities have been diagnosed with colorectal cancer in the last few years, such as actors James Van Der Beek, diagnosed in 2023, and Chadwick Boseman, who passed from colon cancer at 43 years old.
“This, coupled with colorectal cancer increasing in young people, has led to more discussions about colorectal cancers and the signs people should look out for,” Issaka said. “I suspect that the combination of these factors has made millennials and Gen Zers pay closer attention to their stools than the generations before them.”
The poop abnormalities were also more common among people already diagnosed with irritable bowel syndrome (IBS), a chronic GI disorder. This group was especially likely to see undigested food (40%), unusual shape (38%), and blood in their stool (22%).
“IBS presents with a range of symptoms,” Jennifer Christie, MD, FASGE, AGAF, division director of Gastroenterology and Hepatology at the University of Colorado Anschutz Medical Campus, told Health. Seeing unusual shapes or undigested food in stool can be typical for those with IBS, but blood is not associated with the condition, Christie noted.
Not every change in bowel habits is a sign of something sinister, but some symptoms are more threatening than others, and persistent abnormalities are worth paying attention to.
According to Issaka, two GI symptoms are the most concerning: blood in stool or on toilet paper and changes in poop caliber (thickness), especially pencil-thin stools. These symptoms could indicate colorectal cancer.
Blood could also be a sign of hemorrhoids or an anal fissure, which is a painful tear of the anal tissue, Christie said. Unusually shaped poops can also signal other digestive problems—most commonly constipation (hard, separate lumps) and diarrhea (loose or watery stool).
A small amount of mucus in stool is usually nothing to worry about. Since mucus lines the GI tract, it can sometimes show up in normal stool. However, large amounts of mucus with diarrhea may indicate an intestinal infection, and mucus accompanied by blood could be a sign of inflammatory bowel disease (IBD) or colorectal cancer.
Spotting undigested food in the toilet bowl may simply mean you’ve been eating too quickly. “Something you ate that is difficult to digest (like corn, peppers, and some legumes) may also cause these changes,” Christie said. In some cases, though, it could signal a problem with absorption or indicate dumping syndrome, a condition associated with surgery on the digestive tract.
As for color, there’s a range of what’s normal. Shades of brown and green are largely considered regular, and even red or blue poop can simply be the result of eating foods with artificial dyes or naturally bright colors, like beets.
Yet, light- or clay-colored stool can mean that something is wrong with your bile system, the drainage system of the gallbladder, liver, and pancreas. Black stool is most often a sign of bleeding in your intestinal tract.
Some of these irregularities, like undigested food and unusual colors, are typically harmless. But Issaka said if any of these symptoms persist or overlap with other concerns, like unintentional weight loss or unexplained abdominal pain, it’s time to consult a medical professional.
Experts also stressed that blood in stool always warrants a visit to the doctor.
Don’t hesitate to speak up—21% of Health survey respondents avoided seeking care for a digestive issue, primarily due to thinking it was not important enough (9%) and embarrassment (8%).
“These frank conversations are necessary to raise awareness about normal bowel patterns and when medical professional help is needed,” Issaka said.
Health.com surveyed 2,001 adults living in the U.S. from June 11-19, 2025. The survey was fielded online via a self-administered questionnaire to an opt-in panel of respondents from a market research vendor. In order to qualify, respondents must be over the age of 18 and living in the U.S. Quotas were implemented in sampling using benchmarks from American Community Survey (ACS) from the U.S. Census Bureau for age, race/ethnicity, and household income.
