Do Antibiotics Cause Constipation? An Expert Doctor Explains

About the expert

Linda Yancey, MD, is a board-certified physician in infectious disease and internal medicine with over two decades of experience practicing in Texas. She completed her residency at Mayo Clinic in Scottsdale, Arizona, and pursued a fellowship at Baylor College of Medicine in Houston. Currently, Dr. Yancey serves as an infectious disease specialist at Memorial Hermann Hospital in Houston.

Highlights

• Antibiotics are more commonly associated with diarrhea.
• Changes in diet, hydration, and activity levels contribute to constipation.
• Incorporating healthy lifestyle changes can help relieve constipation.
• Call your doctor if constipation persists.

Antibiotics are among the most widely prescribed medications, with over 236 million prescriptions written in the United States in 2022, according to the Centers for Disease Control and Prevention (CDC). That’s roughly seven prescriptions for every 10 people in outpatient care. While these medications are essential for fighting bacterial infections, they can also throw your digestive system off balance in ways patients don’t always anticipate. If you’ve started such a prescription and suddenly feel like your tummy is sluggish, it’s possible there’s an explanation.

Typically, antibiotics are not directly the cause of constipation and are more likely to cause diarrhea. But if you’re feeling backed up while on these medications, there may be other factors at play.

Ahead, Linda Yancey, MD, a board-certified infectious disease doctor at Memorial Hermann Hospital in Houston, reveals whether your antibiotic might be linked to constipation and what happens in your digestive system when you take antibiotics.

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Do antibiotics cause constipation?

“Antibiotics do not cause constipation,” says Dr. Yancey. “Rather, their main side effect is diarrhea.”

That’s because the gut is home to trillions of bacteria that aid digestion and keep bowel movements regular. “Up to 40% of the volume of stool is bacteria. When people are on antibiotics, they kill off these good bacteria that help us digest our food,” she explains. This disruption to the gut microbiome can throw digestion off balance, often leading to looser stools rather than constipation.

In some cases, antibiotic use can lead to a more serious complication caused by a bacterium called Clostridioides difficile (often referred to among healthcare professionals as “C. diff”). Dr. Yancey says C. diff “can result in severe diarrhea that often requires hospitalization.”

C. diff infection can cause symptoms such as watery diarrhea, fever, loss of appetite, nausea, and abdominal pain. People most at risk include older adults, those with weakened immune systems, and individuals who have recently been hospitalized or undergone long-term antibiotic treatment.

If you experience persistent diarrhea after taking antibiotics, it’s important to seek medical attention immediately.

Other reasons you may be constipated while taking antibiotics

Although antibiotics themselves do not cause constipation, you might still experience it while on these medications. In most cases, constipation results from other factors related to being sick or changes in routine.

Possible reasons for constipation during antibiotic use include:

• Dietary changes: When feeling unwell, people often eat fewer fiber-rich foods, such as fruits, vegetables, and whole grains, which can slow digestion. It’s natural to want to take it gentler on your system when you’re not 100%, but when you start to feel better, Dr. Yancey says it’s important to know: “Fresh fruits and vegetables are very important to good intestinal health. The gut microbiome is incompletely understood, but we are beginning to realize that the foods we eat can have a profound effect on these bacteria.”
• Dehydration: Not drinking enough water can make stools harder and more difficult to pass.
• Reduced physical activity: Being sick can mean more time resting and less time moving—which is good for recovery—but which can also slow digestion.
• Other medications: Pain relievers, antihistamines, and certain antacids can contribute to constipation.

How to get relief from constipation

If you’re feeling blocked up, try these simple remedies to help get things moving:

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Drink more water

Hydration is key to maintaining healthy digestion. Warm liquids, such as herbal tea or warm lemon water, may also help stimulate bowel movements.

Increase your fiber intake

A diet rich in fiber can help regulate digestion and promote regular bowel movements. Whole grains (like oatmeal, brown rice, and whole-wheat bread), fresh fruits (such as pears, apples, and berries), and vegetables (including leafy greens, carrots, and broccoli) provide the necessary fiber to keep things on track. Legumes, such as beans and lentils, are also excellent sources of fiber.

Get moving

Regular physical activity can stimulate the digestive tract and help relieve constipation. Even light exercise, such as a 15- to 30-minute walk, can encourage a bowel movement. Yoga poses for the gut, such as those that involve twisting motions, may also be beneficial in promoting digestion.

Try a natural remedy

Prunes and prune juice are well-known natural laxatives due to their high fiber and sorbitol content. Other natural options include flaxseeds, chia seeds, and probiotics, which support a healthy gut microbiome.

Consider a gentle laxative

If constipation persists despite dietary and lifestyle changes, an over-the-counter osmotic laxative like Miralax can help by drawing water into the intestines, making stools easier to pass. Stool softeners and fiber supplements, such as psyllium husk (Metamucil), may also be effective. However, always check with your doctor before using any laxative, especially if you are on antibiotics or other medications.

How else can antibiotics affect your digestion?

Even though constipation isn’t a side effect, antibiotics can cause other digestive issues, including:

• Diarrhea: This is the most common digestive side effect of antibiotics. “Almost everyone on antibiotics will have some loose stools,” says Dr. Yancey.
• Nausea: Some antibiotics irritate the stomach lining, causing queasiness, especially when taken on an empty stomach. Eating a small meal before taking antibiotics can help minimize this effect.
• Gas and bloating: As antibiotics alter the gut microbiome, they can lead to temporary imbalances that cause excess gas production and bloating.
• Abdominal cramps: Changes in gut bacteria and stool consistency can sometimes trigger mild cramping.

When to see a doctor

If you’re dealing with persistent constipation that doesn’t improve with home remedies, it’s important to speak with your doctor. Seek medical attention if you experience any of the following, but not limited to:

• Constipation lasting more than a few days
• Severe abdominal pain or bloating
• Blood in your stool
• Inability to pass gas or stool

For daily wellness updates, subscribe to The Healthy by Reader’s Digest newsletter and follow The Healthy on Facebook and Instagram. Keep reading:

• • 6 Best Ways To Restore Your Gut Health After an Antibiotic, from Expert Doctors
  • Antibiotic Resistance: 5 Ways To Prevent It, from a Doctor of Pharmacy
  • What’s the Strongest Natural Antibiotic? Expert MDs Reveal
  • 15 Foods That Are Natural Laxatives
  • 5 Drinks That Make You Poop Immediately, From a Gastroenterologist