Written by Dr. Bharat Pothuri, MD, FACG

What Causes Rectal Bleeding?

A Friendly Guide from Gastrodoxs.com

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:

1. Hemorrhoids
   
   • Swollen veins that itch, burn, or bleed
   • Bright red blood on tissue or in the toilet
2. Anal Fissures
   
   • Small tears in the skin
   • Sharp pain during or after bowel movements
3. Diverticular Disease
   
   • Small pouches in the colon wall
   • Can bleed or get infected
4. Inflammatory Bowel Disease (IBD)
   
   • Includes Crohn’s disease and ulcerative colitis
   • Ongoing inflammation causes bleeding and mucus
5. Colon Polyps or Cancer
   
   • Polyps can turn into cancer over time
   • Bleeding may be hidden (occult) or visible
   • Early screening is vital
6. Infections
   
   • Bacteria or viruses that irritate the colon
   • May cause blood, diarrhea, and cramps
7. Proctitis
   
   • Inflammation of the rectum lining
   • Caused by infections, IBD, or radiation

Section 5: Table – Compare Common Causes

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.

External Resources

• Mayo Clinic – Hemorrhoids
• NIH – Crohn’s and Colitis Info
• CDC – Colon Cancer Screening

Final Thoughts

Rectal bleeding is common—and often treatable.

We hope this guide helped answer:

• “What does rectal bleeding mean medically?”
• “Why am I bleeding after a bowel movement?”
• “Is blood in stool always serious?”

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.