Can Flagyl be used to treat diarrhea?

In some cases, Flagyl (metronidazole) might be used to treat certain types of infections due to bacteria or protozoa (parasites) that include diarrhea as a symptom. It is not used to treat most cases of acute diarrhea (viral gastroenteritis or food poisoning), which are usually self-limiting and do not typically need treatment with an antibiotic. Do not use Flagyl to treat diarrhea unless a doctor has specifically prescribed it for this use.

If you have severe diarrhea that is watery, bloody, or contains mucus, stomach or intestinal cramping or pain, or a fever, call your doctor right away. Also call your doctor or nurse if you are 65 years of age or older or immune-compromised and develop diarrhea.

Avoid any over-the-counter (OTC) antidiarrheal medicine (for example, loperamide or Pepto-Bismol) unless your doctor recommends it. Doctors generally do not recommend using OTC antidiarrheals for people who have bloody stools or fever, which can be signs of infection with bacteria or parasites.

If you have diarrhea, it is important to drink oral rehydration fluids (for example, Pedialyte found at groceries or pharmacies) to help prevent dehydration. Contact your doctor or your child's doctor for further advice on acute diarrhea.

Diarrhea diseases treated with Flagyl

Clostridioides difficile

Flagyl (metronidazole) might be used to treat diarrhea due to the anaerobic bacterium Clostridioides difficile (C. diff), but it is no longer the first-choice treatment for C. diff. due to rising antibiotic resistance. Other medicines besides metronidazole (such as vancomycin or fidaxomicin) are preferred instead for this infection. In some cases where vancomycin or fidaxomicin are not accessible or affordable, metronidazole might be used.

Flagyl also treats Bacteriodes fragilis, an organism normally found in the colon that may cause inflammatory diarrhea, infection or abscess. Enterotoxigenic B. fragilis diarrheal disease may cause symptoms such as abdominal pain, tenesmus (the feeling that you need to pass stools, even though your bowels are already empty) and inflammatory diarrhea.

For those with repeat C diff. infections, new treatments such as fecal microbiota transplants and oral treatments are now available.

Related: FDA Approves Vowst, First Microbiota-based Oral Capsule to Reduce C. Diff

Related questions

• Does Flagyl treat UTI infections?
• What can I do about the metallic taste of Flagyl?
• Does Flagyl make your urine dark?

Protozoas

Metronidazole also is used to treat protozoas (parasites), organisms that cause Giardiasis or Amebiasis that are also associated with diarrhea.

In some cases, your healthcare provider may have you submit a stool sample to help determine if you have a possible bacterial or parasitic infection.

Other uses

Flagyl (metronidazole) is an antibiotic that is used to treat many other different kinds of bacterial infections, including those of the:

• stomach
• vagina
• liver
• skin
• joints
• lungs
• heart
• bloodstream
• brain and spinal cord.

It may be given orally or by injection and is often combined with other antibiotics for serious infections. Do not use metronidazole to treat any condition that has not been evaluated by your doctor.

Flagyl has no action on viral infections such viral gastroenteritis (the “stomach flu”) or COVID-related diarrhea. However, your doctor may recommend medicine to treat the symptoms of diarrhea or other treatments. Knowing when you should seek medical advice is critical to help prevent serious or life threatening complications.

This is not all the information you need to know about Flagyl (metronidazole) for safe and effective use, or about diarrhea, and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.