Stool Color Reveals Disease! How to Identify Normal and Cancer-Risk Stool Characteristics

Did you know? Stool color and characteristics can signal serious diseases. Quickly check which stool types are normal or indicate colorectal cancer risk, with medical guidelines that health-conscious people should not overlook.

The excretory system is a key mechanism clearly reflecting our internal health. Particularly, "stool" is often overlooked, but its color and shape can accurately warn of digestive, intestinal diseases, or even cancer in advance.

Stool characteristics according to the Bristol Stool Chart.

Medically, stool is classified into seven types for easier intestinal health assessment, as follows.

• Type 1: Small, hard lumps resembling chestnut seeds: Requires straining and indicates constipation, often caused by low fiber intake such as insufficient vegetables and fruits, or lack of regular bowel habits, which may cause injury during defecation.
• Type 2: Sausage-like but formed of small lumps: Can be separated into small lumps and still requires straining, also characteristic of constipation.
• Type 3: Sausage-shaped with cracks on the surface: Requires mild straining, indicating a moderate amount of dietary fiber and a healthy range.
• Type 4: Smooth, soft sausage-shaped stool: No cracks on the surface and requires minimal straining; considered the ideal stool form.
• Type 5: Soft blobs with clear edges: Requires almost no straining, often seen in patients with colitis or irritable bowel syndrome (IBS).
• Type 6: Fluffy pieces with ragged edges, mushy consistency like porridge: Individual pieces are not clearly separated, require little straining, seen in colitis, IBS, or gastrointestinal infections.
• Type 7: Watery, no solid pieces: Liquid consistency that flows without straining, common in severe diarrhea cases such as cholera or food poisoning.

What do thin or floating stools indicate?

Beyond the 7 types above, stool shape and buoyancy should not be overlooked.

• Narrow, pencil-like stool: May signal obstruction in the colon or rectum caused by tumors or colorectal and anal cancer. If thin stools persist for more than two weeks, or if abdominal pain and blood occur, medical consultation should be immediate.
• Floating stool: Associated with excessive intestinal gas or a high-fiber diet (mainly vegetables and fruits, low meat and fat), and may also be due to malabsorption. Floating stool alone without other symptoms is usually not worrisome, but if accompanied by abnormal weight loss, pale color, or blood, detailed examination is advised.

Decoding stool color: warning signs of serious diseases.

Generally, healthy stool is yellow or brown due to bilirubin, a yellow pigment produced by the liver and gallbladder that aids fat digestion in the small intestine. When body systems are disrupted, stool color changes as follows.

• Dark brown: Results from prolonged retention of waste in the colon due to constipation.
• Pale, white, or gray: Indicates abnormalities in bile production or secretion, possibly signaling liver, gallbladder, or bile duct diseases such as gallstones blocking bile ducts, bile duct cancer, liver cancer, or pancreatic cancer obstructing bile flow. Some antacids or barium used in X-rays may temporarily turn stool gray for 1-2 days.
• Green: Occurs when stool passes through the intestine too quickly for bacteria to change bile color, as in severe diarrhea, colitis, irritable bowel syndrome, or Salmonella and amoebic infections. It can also result from swallowing green mucus, side effects of laxatives, iron supplements, or eating chlorophyll-rich foods and algae.
• Orange: Often caused by certain medications or supplements, such as rifampicin, beta-carotene, or consuming large amounts of beta-carotene-rich fruits and vegetables like carrots, tomatoes, and ripe mangoes.
• Stool containing fat/oil with strong foul odor: Indicates deficiency of pancreatic lipase enzyme or bile duct obstruction, impairing fat digestion and absorption. Common in pancreatitis, cystic fibrosis,fibrosis,milk intolerance, or side effects of certain medications like Orlistat.
• Dark black, tar-like: A dangerous sign of bleeding in the upper gastrointestinal tract such as esophagus, stomach, or upper small intestine, caused by ulcers, gastritis, stomach cancer, or cirrhosis. Blood reacts with stomach acid turning stool black. Iron supplements or eating red meat can also darken stool.
• Normal-colored stool with fresh blood or red stool: Indicates bleeding in the lower gastrointestinal tract such as colon or rectum, from colitis, food poisoning, dysentery, colon polyps, hemorrhoids, or possibly colorectal or anal cancer. Foods like red meat or red/purple drinks can also cause red stool.

Observations about blood in stool that should not be ignored.

When bleeding accompanies bowel movements, do not assume it is only hemorrhoids or anal fissures, as it may signal malignancy. Observe blood characteristics to inform your doctor precisely, as follows.

1. Clear blood coating the stool surface or mixed within the stool.
2. Drops of blood after defecation or mixed during bowel movement.
3. Blood that is bright red or tarry black in appearance.
4. Blood stains on toilet paper after wiping.

The amount of blood does not indicate disease severity. If you notice abnormal stool or bowel symptoms, promptly consult a specialist for diagnosis and treatment.

Regularly observing stool color and characteristics is an easy and crucial basic health check. Changes in stool shape and color reflect diet, digestive illnesses, and early warning signs of serious diseases like colorectal cancer. Not ignoring stool abnormalities and seeking medical advice early increases chances of effective diagnosis and treatment.

Source: Professor Dr. Jumpon Wilasrasamee, Department of Surgery, Faculty of Medicine Ramathibodi Hospital, Mahidol University.