STD Cause Diarrhea: Symptoms, Treatments & What to Know

Can an STD cause diarrhea? Yes — certain sexually transmitted infections (STIs) can cause diarrhea, especially when the rectum or digestive tract is involved.

Infections such as chlamydia, gonorrhea, HIV, and some forms of hepatitis can affect the gastrointestinal system. When this happens, symptoms may include diarrhea, rectal pain, abdominal cramping, and painful bowel movements.

This guide explains which STDs can cause diarrhea, how to recognize symptoms, and when testing is recommended.

Key Takeaways

• Rectal STDs can cause diarrhea and painful bowel movements.
• Chlamydia, gonorrhea, HIV, and hepatitis are common causes.
• Chronic diarrhea lasting more than 2 weeks requires evaluation.
• Testing is essential because symptoms may be mild or overlooked.

How STDs Can Cause Diarrhea

Some sexually transmitted infections infect the rectum (proctitis) or weaken the immune system, allowing gastrointestinal inflammation to develop.

This may result in:

• Frequent loose stools
• Rectal pain
• Mucus or blood in stool
• Abdominal cramping
• Painful bowel movements

If diarrhea appears alongside other STD symptoms, such as discharge, sores, fever, or swollen lymph nodes, infection should be considered.

Common STDs That Can Cause Diarrhea

Rectal Chlamydia

Chlamydia can infect the rectum, especially after receptive anal sex. Symptoms may include:

• Rectal pain
• Discharge
• Bleeding
• Diarrhea

See more at chlamydia symptoms.

Rectal Gonorrhea

Gonorrhea can cause inflammation of rectal tissue (proctitis), leading to:

• Painful bowel movements
• Rectal discharge
• Diarrhea

Learn more at gonorrhea symptoms.

HIV

HIV can cause both early flu-like symptoms and chronic diarrhea as the immune system weakens.

Review early signs at HIV symptoms guide.

Hepatitis A & B

Hepatitis infections can cause:

• Nausea
• Diarrhea
• Abdominal pain
• Jaundice

Other Causes: Syphilis & Herpes

While less common, syphilis and herpes can cause rectal sores or inflammation that make bowel movements painful and sometimes mistaken for diarrhea.

Acute vs. Chronic Diarrhea

Acute diarrhea: Fewer than 14 days

Chronic diarrhea: More than 14 days

Chronic diarrhea may signal untreated infection or immune suppression and should always be evaluated.

When Diarrhea Might NOT Be an STD

Not all diarrhea is STD-related. Other causes include:

• Food poisoning
• Viral gastroenteritis
• IBS or IBD
• Medication side effects

If diarrhea follows sexual exposure or is paired with rectal pain or discharge, STD testing is recommended.

Diagnosis

STD-related diarrhea is diagnosed using:

• Urine testing
• Rectal swabs
• Blood tests (HIV, hepatitis, syphilis)

A 10-panel STD test screens for common infections in one visit.

You can also find confidential testing at a local STD testing center near you.

Treatment

Treatment depends on the cause:

• Bacterial infections (chlamydia, gonorrhea): Antibiotics
• Viral infections (HIV, hepatitis): Antiviral therapy

Hydration is important during recovery to prevent dehydration.

When to Seek Medical Care Immediately

• Diarrhea lasting more than 2 weeks
• High fever
• Severe abdominal pain
• Blood in stool
• Unintentional weight loss

Early diagnosis prevents complications like pelvic inflammatory disease (PID), infertility, joint infections, or immune damage.

Long-Term Complications if Untreated

• Reactive arthritis
• Gonococcal arthritis
• Pelvic inflammatory disease
• Infertility
• AIDS (advanced HIV)

Prevention

• Use condoms during vaginal, anal, and oral sex
• Limit new sexual partners
• Get tested regularly
• Vaccinate for hepatitis B

Bottom Line

Yes, some STDs can cause diarrhea — especially rectal infections or HIV-related immune suppression.

If diarrhea occurs alongside rectal pain, discharge, sores, or other STD symptoms, testing is the safest next step.

Confidential testing is available at a local clinic near you.

FAQs

Can chlamydia cause diarrhea?

Yes. Rectal chlamydia can cause inflammation leading to diarrhea and rectal discomfort.

Can gonorrhea cause diarrhea?

Yes. Rectal gonorrhea can cause painful bowel movements and loose stools.

Is diarrhea an early HIV symptom?

It can be. HIV may cause early flu-like symptoms or chronic diarrhea later in infection.

Should I get tested if I have diarrhea after anal sex?

Yes. Rectal swab testing is recommended if symptoms appear after exposure.