Can antibiotics cause diarrhea?

If you have ever gone to the doctor for an infection, you have probably been prescribed antibiotic treatment. These medications are formulated to kill harmful bacteria that cause infections, and like most medications, antibiotics come with a risk of side effects. 

One of the most common complaints is antibiotic-induced diarrhea. Generally, diarrhea clears up after you stop taking the antibiotics. But while you’re on antibiotics, you may wonder how to stop yourself from running to the toilet and if you should tell your doctor what’s happening. You may also wonder whether you can discontinue your antibiotics to resolve the problem. 

To help you navigate this uncomfortable side effect, three healthcare professionals explain why antibiotics cause diarrhea, the worst antibiotics for diarrhea, and how to stop diarrhea from antibiotics.

Can antibiotics cause diarrhea? 

It’s not unusual for antibiotics to cause loose stools, says Jodie Pepin, Pharm.D., the clinical pharmacy program director at Harbor Health. Research suggests that 5% to 35% of people taking antibiotics develop antibiotic-associated diarrhea.

Dr. Pepin says there’s a  reason these medicines can send you to the toilet: Antibiotics disrupt the natural balance of good and bad intestinal bacteria. When an antibiotic kills the good bacteria in your gut, your body can’t process poop into its fully-formed, semi-soft consistency. However, the risk of diarrhea varies depending on the type of antibiotic.

“Different classes of antibiotics treat different types of bacteria,” says Christina M. Madison, Pharm.D., FCCP, founder of The Public Health Pharmacist in Las Vegas. 

“When we are unsure what the infection is being caused by, we typically use what’s called ’empiric’ therapy with a ‘broad spectrum’ antibiotic,” she says. These broad-spectrum antibiotics kill good and bad bacteria, which might temporarily impede your body’s ability to make fully-formed stools. The result? Diarrhea.

According to the Mayo Clinic, antibiotic-induced diarrhea typically starts about a week after the first antibiotic dose. 

Don’t stop taking your prescribed antibiotic if you experience this unpleasant side effect. Instead, report the frequency and severity to your healthcare provider to help you navigate your options, says Minesh Amin, DO, medical director at Regenerate Medical Concierge in Henderson, Nevada. 

Which antibiotics cause diarrhea?

Most antibiotics have the potential to cause diarrhea. However, Dr. Madison says “targeted” antibiotics—drugs that are effective against just one bacterial type—are less likely to impede healthy stool formation. Broad-spectrum antibiotics designed to kill a wide variety of microorganisms are hardest on the digestive system. But the likelihood of diarrhea occurring  isn’t necessarily what your provider considers before prescribing the antibiotic.

“We can never select an antibiotic with the intent to try and avoid antibiotic-induced diarrhea,” says Dr. Amin. “The choice of antibiotic is always based on the greatest likelihood of eradicating the active infection,” he explains.

Antibiotic drug classes associated with the most significant risk of antibiotic-induced diarrhea include:

• Lincosamides (like clindamycin) pose the highest risk of antibiotic-induced bacteria, according to a meta-analysis of more than 2 million reports of reactions to antibiotics. 
• Beta-lactams, such as amoxicillin, penicillin, ampicillin, and cephalosporins (cephalexin, cefpodoxime, and cefdinir, for example)
• Macrolides, such as erythromycin, clarithromycin, and azithromycin (though the latter has a slightly lower likelihood of disrupting gut bacteria, according to Dr. Madison)
• Fluoroquinolones, such as ciprofloxacin and levofloxacin, which Dr. Amin says are commonly prescribed for urinary tract infections and respiratory tract infections

Risk of C. difficile-associated diarrhea

In some cases, multiple courses of antibiotics can cause a bacteria called Clostridioides difficile (C. diff) to run rampant in the colon. 

“When it is allowed to overgrow … C. diff releases a toxin that damages the lining of our gut,” Dr. Pepin explains. “The result of this is an infection that causes severe diarrhea and inflammation.”

Unlike other antibiotic-induced diarrhea, C. diff is highly contagious and dangerous, making it a concern among hospitalized patients. About 9% of adults 65 or older with a C. difficile infection die within 30 days of diagnosis. Dr. Pepin says good hand-washing hygiene is essential to stopping the spread. 

Symptoms of antibiotic-associated diarrhea

Most cases of antibiotic-associated diarrhea are mild, and symptoms include:

• Loose, watery stools
• Frequent bowel movements (three times per day or more)

Symptoms of C. diff infection are usually more severe. They include:

• Loose, watery stools that are often uncontrollable
• Frequent bowel movements
• Abdominal pain
• Gastrointestinal cramps
• Nausea
• Poor appetite
• Fever

If you show signs of a C. difficile infection, consult a healthcare professional immediately. 

What should I eat if I have diarrhea from antibiotics?

Dr. Amin suggests eating more starchy foods because they are easy to digest. Additionally, probiotic-rich foods can help repopulate your gut with good bacteria. He also emphasizes the importance of staying hydrated.

“One of the most common recommendations when experiencing antibiotic-induced diarrhea is the BRAT diet. This includes bananas, rice, applesauce, and toast,” he says. Dr. Amin also suggests eating yogurt for the following reasons: 

• It contains probiotics. Yogurt’s probiotics can help offset the antibiotics’ eradication of good gut bacteria. Read the label to ensure you buy yogurt containing live active cultures.
• It can soothe gut inflammation. Plain yogurt can have a cooling effect on the gut, which might help settle your stomach after antibiotics.
• It contains essential nutrients. “Yogurt is packed with essential nutrients such as calcium, B-12, and vitamin D,” Dr. Amin says.

Drink fluids with electrolytes. Dehydration is a severe risk for anyone with diarrhea. Watery diarrhea means that many of the fluids you consume go straight into the toilet instead of being absorbed by your body. When fluid is lost, you also lose electrolytes (essential minerals like sodium, potassium, and magnesium). Drs. Amin and Pepin suggest rehydration with electrolyte drinks, such as Pedialyte, Gatorade, Powerade, and broths.

“Electrolyte solutions in general are far superior to water when a person has diarrhea because the electrolytes allow quicker absorption of the water into the body,” Dr. Amin says.

There are also foods to avoid when experiencing antibiotic-induced diarrhea. Dr. Pepin recommends staying away from red meat, while Dr. Amin says spicy and greasy foods can worsen diarrhea. He also suggests limiting caffeine and alcohol, which stimulate the gut and increase bowel movements.

How to stop diarrhea from antibiotics

Antibiotic-induced diarrhea will often go away on its own after a few days. However, there are self-care measures to help relieve discomfort while you wait for it to clear up. Diarrhea management tips from the experts at the Cleveland Clinic include:

• Eat bland, low-fiber, starchy foods until the diarrhea resolves.
• Avoid fried and spicy foods.
• Avoid alcohol and caffeine while taking antibiotics.
• Take probiotics to rebalance gut bacteria and stop the diarrhea.
• Drink plenty of water, fruit juices, and electrolyte drinks to stay hydrated.
• Consult your healthcare provider about anti-diarrheal medications such as loperamide (Imodium A-D) or possibly Pepto-Bismol.

Clinical trials suggest that Lactobacillus rhamnosus GG (LGG) and Saccharomyces boulardii (S. boulardii) are the best probiotics for diarrhea caused by antibiotics. These strains are widely available in oral probiotic supplements.

“One to two loose stools per day is common from antibiotic therapy,” Dr. Madison says. “If you are experiencing significant side effects from your medication therapy, you should reach out to the prescribing provider before discontinuing therapy.”

Call your healthcare provider immediately if you experience additional symptoms such as weakness, fever, or loss of appetite. “A doctor can do a stool sample to test for C. diff and treat it quickly,” Dr. Pepin says.

How to prevent diarrhea from antibiotics

First, only take antibiotics when prescribed by a healthcare professional to treat a bacterial infection, says Dr. Madison. Antibiotics are ineffective against viruses such as the common cold or seasonal flu.

Beyond that, prevention of antibiotic-associated diarrhea involves the same practices as treatment options:

• Take the right drug for the right bug. Dr. Madison suggests taking the most targeted treatment for your infection versus a broad-spectrum antibiotic. This reduces the chance of disrupting your gut microbiome.
• Add a probiotic. Dr. Amin says nourishing your gut with good bacteria can help prevent antibiotic-induced diarrhea and treat it when it occurs.
• Keep protecting your digestive tract after the antibiotics are finished. Stave off post-antibiotic diarrhea by eating yogurt with live active cultures or taking oral probiotic supplements for about a week after completing your antibiotic course, recommends Dr. Pepin.