Warning: This article contains discussion of cancer which some readers may find distressing.
A specialist has shared five potential warning signs of colon cancer that shouldn’t be ignored.
Many people feel awkward discussing bowel habits, but staying silent can delay getting checked when something isn’t right.
Colon cancer (also known as bowel cancer) can often be treated successfully when it’s found early. The challenge is spotting possible symptoms and acting on them before the disease spreads, because treatment can become more difficult at that point.
According to The American Cancer Society, 108,860 new cases of colon cancer have been detected in 2026 so far — and it’s only March.
Here are the symptoms to watch for, as highlighted by Jeremy Clark, a consultant general surgeon at Nuffield Health in Brighton, UK.
Speaking with The Mirror, Clark explained that blood in your stool is a symptom that needs attention, even if it looks different from what you might expect.
‘passing blood when you go to the toilet is a worrying feature that you should flag’ to your doctor, and that if you’re not sure what it looks like – the blood can look almost black in color and darkens as time passes.
“If you’re bleeding from the beginning of your colon, it has got to travel three or four feet before it comes out with your waste material, so it will turn very dark black,” he said.
However, ‘if you’re bleeding from something lower down in the bowel, closer to your bottom, it will come out bright red’.
He added: “If you see blood in the stools, particularly darker-colored blood or blood that’s actually mixed in with the stools, just once and it’s significant, that should be reported to your doctor straight away. Don’t wait for that to keep on happening.”
He also warned that blood appearing repeatedly over a period of weeks should be raised with a healthcare professional.
A noticeable change in your bowel routine
Another sign to take seriously is a sudden shift from your normal pattern — whether that means constipation, going more often, or looser stools that don’t settle.
According to Clark, ‘if your bowels go from working once a day like clockwork, and then suddenly you’re going two or three times a day and the bowels are a bit looser, that’s something that needs to be looked into.”
He noted that a short-lived change that resolves within a couple of days may be less concerning, but ongoing symptoms should be checked.
Unexplained weight loss
While planned weight loss can be beneficial, dropping weight without trying can be a warning sign that should be investigated.
“Bowel cancers can cause you to lose weight by having an impact on how your digestion is working,” said Clark. “There’s a whole host of symptoms, but the problem is that they all cross over with other less serious problems, such as hemorrhoids or irritable bowel syndrome (IBS), so people often ignore or easily dismiss these symptoms.”
Although colon cancer is more common in people over 50 or those with a family history, diagnoses among younger adults — including under 30s — have been increasingly reported in recent years.
Ongoing abdominal pain
Persistent discomfort or pain in the abdomen is another symptom that shouldn’t be brushed aside, particularly if it’s unusual for you.
According to Clark: “Bowel cancers can cause abdominal pain. This tends to be a later feature, but it can occur early on, too.”
Frequent bloating
If bloating becomes a regular issue — for example after meals, throughout the day, or even first thing in the morning — it’s worth discussing with a doctor, especially if it’s persistent or worsening.
“People often feel quite bloated if there’s something wrong going on in the bowel,” revealed Clark.
Overall, if you’re concerned, Clark advises people not to ‘sit’ on symptoms and to get them assessed.
If you’ve been affected by any of these issues and want to speak to someone in confidence, contact the American Cancer Society on 1-800-227-2345 or via their live chat feature, available 24/7 every day of the year.