Colorectal cancer can cause changes in your bowel habits, bleeding, abdominal discomfort, and general symptoms like fatigue and weight loss, but early on it may cause no symptoms at all.

Quick Scoop: Key Signs to Watch

1. Bowel changes that don’t go away

These are some of the most common warning signs.

  • Diarrhea that lasts more than a few days
  • Constipation that doesn’t improve with your usual fixes
  • Stool that looks narrower than usual (sometimes called “pencil‑thin” or ribbon‑like)
  • Feeling like you still need to have a bowel movement, even right after going
  • Needing to rush to the bathroom more often than normal

If these changes persist for more than a couple of weeks, it’s important to speak with a doctor, especially if you’re over 45 or have risk factors.

2. Blood where it shouldn’t be

Bleeding can be subtle or obvious, and people sometimes blame it on hemorrhoids and delay getting help.

  • Bright red blood on the toilet paper or in the toilet bowl
  • Dark red or very dark, tar‑like stool (can indicate digested blood)
  • Stool that looks mixed with blood or has maroon streaks

Any unexplained rectal bleeding should be checked by a health professional, even if you think it’s “just hemorrhoids.”

3. Abdominal discomfort and bloating

As a tumor grows, it can irritate or partially block the bowel.

  • Cramping or pain in the belly
  • Gas, bloating, or a feeling of fullness
  • A lump or mass you can feel in the abdomen or rectum
  • Nausea or vomiting, especially if paired with severe constipation (possible bowel obstruction)

Severe belly pain plus vomiting and inability to pass gas or stool can be an emergency and needs urgent care.

4. Whole‑body (systemic) symptoms

Cancer can cause slower, whole‑body changes that are easy to overlook or blame on stress or aging.

  • Unintended weight loss (losing weight without trying)
  • Ongoing fatigue, weakness, or shortness of breath from anemia (low red blood cells)
  • Loss of appetite or feeling full very quickly

These symptoms alone don’t prove anything, but together with bowel changes or bleeding, they raise the level of concern.

5. Signs of more advanced spread

When colorectal cancer spreads to other organs, additional symptoms can appear.

  • Jaundice (yellowing of skin or eyes), abdominal swelling, or enlarged liver if it spreads to the liver
  • Bone pain or fractures if it spreads to bone
  • Shortness of breath or persistent cough if it spreads to the lungs
  • Swollen lymph nodes or significant abdominal bloating

These are later‑stage signs and underline why earlier evaluation and routine screening are so important.

Why “no symptoms” is still a big deal

Many people with early colorectal cancer have no symptoms at all; that’s why screening colonoscopies and stool tests are recommended starting around age 45 in many guidelines, sometimes earlier if you have family history or other risk factors. Detecting and removing precancerous polyps can stop cancer before it starts, and finding cancer early greatly improves the chances of cure.

If you’re noticing any combination of persistent bowel changes, blood in your stool, or unexplained fatigue or weight loss, don’t wait for it to “go away on its own” — talk with a doctor or urgent care provider and ask directly whether colorectal cancer should be ruled out.

Important: This is general information, not a diagnosis. If you or someone you know is experiencing these symptoms, especially with rectal bleeding or strong pain, please seek medical care promptly. Information gathered from public forums or data available on the internet and portrayed here.