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What Causes Rectal Bleeding?
In most cases, rectal bleeding is not a sign of something serious -- but that doesn’t mean you should ignore the symptoms. While the most common cause of rectal bleeding is hemorrhoids.
Seeing blood during or after a bowel movement can be scary. You might wonder:
“What does rectal bleeding mean medically?”
“Why am I bleeding after a bowel movement?”
“Is blood in stool always serious?”
I'm Dr. Bharat Pothuri, a gastroenterologist in Houston. I’ve seen many patients worry over even a drop of blood. In this guide, I’ll help you understand why bleeding happens, when to see a doctor, and how Gastrodoxs.com can help.
Section 1: What Is Rectal Bleeding?
Rectal bleeding means blood is coming from the anus or lower digestive tract.
You may see:
Bright red blood
Dark red blood
Black or tarry stool
It may appear on the stool, drip into the toilet, or show up on toilet paper.
“Rectal bleeding can be scary, but many causes are treatable,” says Dr. Pothuri. “The key is knowing when to seek help.”
Section 2: Why Am I Bleeding After a Bowel Movement?
Many people ask this. Common reasons include:
Hemorrhoids – swollen veins in the rectum or anus
Anal fissures – small tears in the skin
Constipation – hard or large stools can cause damage
Straining – pushing too hard breaks tiny blood vessels
Even a small tear can cause bright red blood during or after a bowel movement.
Section 3: Is Blood in Stool Always Serious?
Not always—but sometimes it is.
Mild Causes:
Hemorrhoids
Anal fissures
Minor infections
Serious Causes:
Inflammatory Bowel Disease (IBD) – Crohn’s or ulcerative colitis
Diverticulosis or diverticulitis
Colon polyps or cancer
If the bleeding keeps coming back or you notice other symptoms (like pain or weight loss), it’s time to see a doctor.
Section 4: Most Common Causes of Rectal Bleeding
Here are the most common causes of rectal bleeding:
Hemorrhoids
Swollen veins that itch, burn, or bleed
Bright red blood on tissue or in the toilet
Anal Fissures
Small tears in the skin
Sharp pain during or after bowel movements
Diverticular Disease
Small pouches in the colon wall
Can bleed or get infected
Inflammatory Bowel Disease (IBD)
Includes Crohn’s disease and ulcerative colitis
Ongoing inflammation causes bleeding and mucus
Colon Polyps or Cancer
Polyps can turn into cancer over time
Bleeding may be hidden (occult) or visible
Early screening is vital
Infections
Bacteria or viruses that irritate the colon
May cause blood, diarrhea, and cramps
Proctitis
Inflammation of the rectum lining
Caused by infections, IBD, or radiation
Section 5: Table – Compare Common Causes
Cause
Symptoms
Urgency
Hemorrhoids
Itching, pain, bright blood
Low–Moderate
Anal Fissure
Sharp pain, red blood
Low–Moderate
Diverticular Disease
Cramping, fever, dark blood
Moderate–High
IBD (Crohn’s or UC)
Diarrhea, fatigue, bleeding
High
Polyps or Colon Cancer
Occult bleeding, weight loss
Very High
Infections
Diarrhea, fever, cramps
Moderate
Proctitis
Mucus, urgency, bleeding
Moderate–High
Section 6: Risk Factors and When to Get Help
Risk Factors:
Age over 50
Family history of colon cancer or IBD
Long-term IBD (Crohn’s, ulcerative colitis)
Smoking or heavy alcohol use
Past pelvic radiation
Call Your GI Doctor If:
Bleeding lasts more than 24 hours
You have fever, dizziness, or severe pain
Your stool is black or tar-like
You’ve lost weight or feel weak
“Unexplained rectal bleeding should always be checked,” says Dr. Pothuri.
Section 7: How We Diagnose Rectal Bleeding
At Gastrodoxs in Houston, we use several tests:
1. Anoscopy
A small scope looks at the anal canal
Done in-office, takes a few minutes
2. Flexible Sigmoidoscopy
Looks at the rectum and lower colon
Helps detect inflammation or growths
3. Colonoscopy
Full view of the colon
Can remove polyps or take biopsies
Prep includes clear liquids and laxatives
4. Imaging
CT scan or MRI checks for diverticulitis or masses
5. Lab Tests
Stool tests for hidden blood, infection
Blood tests for anemia or inflammation
Section 8: How We Treat Rectal Bleeding
Treatment depends on the cause. Here’s what we usually recommend:
Hemorrhoids and Fissures
- Sitz baths
- Creams or ointments
- High-fiber diet and stool softeners
- Office procedures like rubber banding
Diverticular Disease
- Antibiotics if infected
- Fiber-rich diet
- Surgery in severe cases
IBD
- Anti-inflammatory drugs
- Biologics for immune control
- Surgery if needed
Colon Polyps or Cancer
- Remove polyps during colonoscopy
- Surgery for cancer
- Chemo or radiation as needed
Infections
- Antibiotics or antivirals
- Rest and fluids
Proctitis
- Medications: steroids, antibiotics, or anti-inflammatories
- Radiation review if linked to prior cancer treatment
Section 9: Prevention Tips
You can lower your risk of rectal bleeding with these steps:
Eat More Fiber
- Aim for 25–30g daily
- Fruits, veggies, beans, and whole grains
Stay Hydrated
- Drink plenty of water
- Limit alcohol and caffeine
Exercise Regularly
- At least 30 minutes most days
- Helps digestion and reduces constipation
Don’t Strain
- Use the bathroom when needed
- Try a footstool for easier posture
Limit Toilet Time
- Avoid long sitting or phone use during bathroom breaks
Section 10: Care at Gastrodoxs.com
At Gastrodoxs.com, we specialize in digestive health for patients across Houston. Dr. Bharat Pothuri and our team provide expert care, testing, and treatment for rectal bleeding and related conditions.
Need help? Schedule a visit with our Houston colon health specialists today.
If you live in Houston, don’t wait. Get care early at Gastrodoxs.com.
About the Author
Dr. Bharat Pothuri is a Board-Certified Gastroenterologist and Hepatologist. With extensive experience in digestive health, he specializes in advanced endoscopic procedures, chronic GI disorder management, and preventive care. Dr. Pothuri is dedicated to providing expert, patient-focused insights to help improve gut health and overall well-being.
Frequently Asked Questions
1. What causes rectal bleeding most often?
Hemorrhoids, fissures, diverticular disease, infections, polyps, or IBD.
2. Is blood in stool always serious?
Not always. Mild causes are common, but ongoing or heavy bleeding should be checked.
3. What does rectal bleeding mean medically?
It usually means irritation, inflammation, or injury in the lower digestive tract.
4. Why am I bleeding after a bowel movement?
Often due to straining, hemorrhoids, or small tears in the anal lining.
5. Can diet help prevent rectal bleeding?
Yes—fiber, water, and regular meals help keep bowel movements soft and regular.
6. When should I see a doctor in Houston?
If bleeding lasts more than 24 hours or comes with pain, dizziness, or black stool.
7. Will I need a colonoscopy?
Many adults do, especially if over 50 or with risk factors.
8. Does an anoscopy hurt?
It may feel like pressure but is quick and well-tolerated.
9. Can kids get rectal bleeding?
Yes. Common causes include anal fissures, polyps, and infections. See a pediatric GI doctor.
10. Where can I find help in Houston?
Visit Gastrodoxs.com to schedule with our local gastroenterology experts.