Gut Health After Antibiotics: What Helps and What to Watch
Medically reviewed by Dr. Michael Teplitsky, MD Last reviewed 2026-09-30
Antibiotic side effects such as diarrhoea usually pass once the course ends, while the evidence for probiotic supplements remains tentative
The NHS says antibiotic side effects such as diarrhoea and feeling sick are usually mild and should pass once you finish your course. Probiotics have shown tentative evidence of reducing antibiotic-associated diarrhea in people who were not hospitalized and in children, though a benefit has not been demonstrated in elderly people. The NHS says to talk to a doctor before taking probiotic supplements if you have an existing health condition or a weakened immune system.
Looking after your gut health after antibiotics begins with understanding that common side effects like diarrhoea and mild nausea typically resolve on their own once you finish your prescribed medication. In the guides we publish here, we cite the study behind each claim, and this one draws on the sources linked below. The National Health Service (NHS) notes that antibiotics target bacterial infections by killing bacteria or stopping them spreading, but they do not work for everything.
A 2017 review reported by the National Center for Complementary and Integrative Health (NCCIH) found that giving probiotics with antibiotics was associated with a decrease of about half in the likelihood of antibiotic-associated diarrhea in people who were not hospitalized. However, this conclusion remains tentative due to moderate study quality, and a benefit has not been demonstrated in elderly people for antibiotic-associated diarrhea. For wider context on digestive function, explore our overview of gut health.
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Antibiotic side effects such as diarrhoea and feeling sick are usually mild and pass once you complete your course of treatment. The NHS explains antibiotic side effects as including diarrhoea and feeling sick. If you experience additional side effects during treatment, you should contact your general practitioner (GP) or the doctor overseeing your care.
Using antibiotics when they are not clinically necessary raises the chance of side effects such as stomach pain, diarrhoea and feeling or being sick.
Clinical Evidence for Probiotics with Antibiotics
In a 2017 review of people who were not hospitalized, giving probiotics with antibiotics was associated with a decrease of about half in the likelihood of antibiotic-associated diarrhea. NCCIH says probiotics have shown promise for preventing antibiotic-associated diarrhea, including diarrhea caused by Clostridium difficile, and the table sets out what each review found for adults, older adults, children and C. difficile.
| Patient Group | Clinical Review Findings | Evidence Caveats |
|---|---|---|
| People who were not hospitalized | A 2017 review of 17 studies with 3,631 participants found that giving probiotics with antibiotics was associated with a decrease of about half in the likelihood of antibiotic-associated diarrhea. | The conclusion was rated tentative because the overall study quality was only moderate. |
| Children | A review of 23 studies involving 3,938 children demonstrated moderate-quality evidence of a protective effect against diarrhea. | No serious side effects were observed in otherwise healthy children except for the infection being treated. |
| Elderly people | A 2016 review of 30 studies (7,260 participants, 5 of the studies in people 65 or older) did not demonstrate a benefit in elderly people. | NCCIH says it is uncertain whether probiotics do not work in elderly people or whether too few studies were done. |
| Clostridium difficile risk | A 2017 analysis of 31 studies with 8,672 patients concluded it is moderately certain that probiotics can reduce the risk of C. difficile diarrhea in adults and children receiving antibiotics. | The patients were mostly in hospital, and using probiotics with antibiotics appears safe except for patients who are very weak or have poorly functioning immune systems. |
NCCIH says probiotics may be helpful for antibiotic-associated diarrhea in young and middle-aged people. For C. difficile, it says the best types, duration and doses are uncertain. NCCIH also says people given probiotics had no more side effects than those who were not.
Probiotic Quality and Regulatory Standards
Probiotics are generally regulated as food products rather than pharmaceuticals, meaning commercial formulations do not undergo the strict regulatory scrutiny required for prescription medicines. The NHS guidance on probiotics notes that there is little evidence to support many of the health claims made about probiotics. NCCIH says many probiotics are sold as dietary supplements, which do not require FDA approval before marketing. The NHS says the product may not contain the stated bacteria, enough bacteria to have an effect, or bacteria that survive long enough to reach your gut.
NCCIH describes the safety picture by health status. The NCCIH warns that the risk of harm from probiotic supplements is greater in people with severe illnesses or compromised immune systems. Possible harms include infections and transfer of antibiotic resistance genes. NCCIH reports that severe or fatal infections have been reported in premature infants given probiotics, and the FDA warned providers. The NHS says to talk to a doctor before taking probiotic supplements if you have an existing health condition or a weakened immune system.
Dietary Fibre and Daily Digestive Function
The NHS says eating plenty of fibre helps digestion and prevents constipation. According to NHS dietary advice on fibre, UK guidelines say adults should aim for 30 grams of fibre a day. A high-fibre eating pattern is also associated with reduced long-term risks of heart disease, stroke, type 2 diabetes, and bowel cancer.
High-fibre foods include wholegrains, pulses, vegetables, fruit, nuts, and seeds. For a closer look at meal planning and nutrient utilization, read our guides on increasing dietary fibre and nutrient absorption, as well as general strategies for metabolic health.
Prudent Antibiotic Use and Prescription Completion
Antibiotics treat or prevent specific bacterial infections by killing bacteria or stopping them spreading, but they do not work for everything. The NHS says many mild bacterial infections get better on their own. The NHS says using antibiotics when they are not needed increases the chance of side effects such as stomach pain, diarrhoea and feeling or being sick.
When a physician determines that an antibiotic is necessary, you should always take the medication exactly as directed. Do not stop or change your course yourself unless a doctor advises it or the warning signs below apply. If side effects bother you, contact your GP or the doctor in charge of your care.
Warning Signs and When to Contact a Doctor
Contact your GP or the doctor in charge of your care if you get additional side effects, and call 999 or go to A&E for signs of a severe allergic reaction. NCCIH says Clostridium difficile can infect the colon of patients who have received antibiotics, causing diarrhea from mild to severe. It is difficult to treat, sometimes comes back, and is more common in people who take antibiotics long term and in elderly people.
The NHS states that allergic reactions to antibiotics occur rarely, most often with penicillin and cephalosporin classes. Mild to moderate allergic reactions involve an itchy raised rash, coughing, wheezing, or tightness in the throat, usually treated with antihistamines; call your GP if you are concerned. In contrast, severe allergic reactions constitute a medical emergency. The NHS says to call 999 or go to A&E for a rash with itchy, red, swollen, blistered or peeling skin, wheezing, tightness in the chest or throat, trouble breathing or talking, or swelling of the mouth, face, lips, tongue or throat. Furthermore, specific drug classes carry unique risks: tetracyclines increase skin sensitivity to sunlight, while fluoroquinolones can very rarely cause disabling, long-lasting or permanent side effects affecting joints, muscles and the nervous system. The NHS says to stop the medicine straight away and see your GP for tendon, muscle or joint pain, or tingling, numbness or pins and needles.
Clinical Boundaries and Who Should Avoid Probiotics
NCCIH says the risk of harm from probiotics is greater in people with severe illnesses or compromised immune systems, and severe or fatal infections have been reported in premature infants given probiotics. Possible harms include infections and transfer of antibiotic resistance genes. The NHS says to talk to a doctor before taking probiotic supplements if you have an existing health condition or a weakened immune system.
If you get any additional side effects, contact your GP or the doctor in charge of your care.
Frequently Asked Questions
How do I restore my gut health after antibiotics?
The sources used here do not give a recovery plan for gut bacteria. General healthy eating with plenty of fibre (wholegrains, pulses, vegetables, fruit, nuts and seeds, with a UK guideline of 30 grams a day) helps digestion and prevents constipation. The NHS notes that common digestive side effects like mild diarrhoea usually pass on their own once you finish your medication course. While probiotics have shown tentative benefits for reducing diarrhoea in some populations, the NHS says they are generally classed as food rather than medicine and there is little evidence to support many health claims made about them.
Should I take probiotics with antibiotics?
A 2017 review of people who were not hospitalized found that giving probiotics with antibiotics was associated with a decrease of about half in the likelihood of antibiotic-associated diarrhea. However, the NCCIH notes this conclusion remains tentative due to moderate study quality. Clinical trials have not demonstrated a preventive benefit in elderly people. If you have an existing health condition or a weakened immune system, the NHS says to talk to a doctor before taking probiotic supplements.
Is diarrhea on antibiotics normal?
Yes, diarrhoea and feeling sick are common side effects of antibiotics according to the NHS. The NHS states that these side effects are usually mild and should resolve naturally once your prescription finishes. If you get any additional side effects, contact your GP or the doctor in charge of your care.
Can antibiotics cause C. difficile?
Yes. NCCIH says Clostridium difficile can infect the colon of patients who have received antibiotics, causing diarrhea that ranges from mild to severe. According to the NCCIH, C. difficile is difficult to treat and more common in elderly patients or individuals taking antibiotics long term. A 2017 analysis concluded it is moderately certain that probiotics can reduce the risk of C. difficile diarrhea in adults and children receiving antibiotics (mostly hospital patients); using them appears safe except for patients who are very weak or have poorly functioning immune systems.
Do probiotics help children on antibiotics?
A review of 23 studies involving 3,938 pediatric patients provided moderate-quality evidence that probiotics have a protective effect against antibiotic-associated diarrhea in children. The NCCIH reported that no serious side effects were observed in otherwise healthy children receiving probiotics alongside antibiotic therapy.
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