Loose stools are one of the most common reasons people call the pharmacy a few days into an antibiotic. If you’re dealing with amoxicillin and diarrhea right now, or you want to head it off before your first dose, this guide gives you a practical plan for before, during, and after your course. It also covers what the probiotic research actually shows, what to eat and drink, and how to tell ordinary antibiotic diarrhea apart from a C. difficile infection that needs a doctor.
Jump to: Why it happens · Your 3-phase plan · Probiotic scorecard · What to eat and drink · Kids · Is it C. diff? · Call vs ER · FAQ
Why amoxicillin and diarrhea go together
Your gut holds trillions of bacteria that help break down food, process bile acids, and crowd out germs that would cause trouble. Amoxicillin can’t tell the bacteria causing your ear or sinus infection apart from many of the helpful ones living in your intestines. When those helpful species drop off, digestion changes, water handling in the colon shifts, and stools get looser. This is called antibiotic-associated diarrhea (AAD).
Most AAD is mild and short-lived. The bigger concern is that a disrupted gut gives an opportunistic germ called Clostridioides difficile (C. diff) a chance to grow.
How common is it?
Across all antibiotics, studies estimate that somewhere between about 5% and 35% of people develop AAD, depending on the drug, the dose, and who is taking it. For plain amoxicillin, the FDA prescribing information for amoxicillin lists diarrhea among its most common side effects, alongside rash, nausea, and vomiting. In the label’s H. pylori treatment trials, where amoxicillin was combined with other drugs, diarrhea was reported in 7% to 8% of patients.
Why Augmentin diarrhea is more common
Amoxicillin-clavulanate (brand name Augmentin) adds clavulanic acid, which protects amoxicillin from enzymes some bacteria use to break it down. That extra ingredient comes with a GI cost. The Augmentin prescribing information names diarrhea or loose stools as its single most common side effect, reported in 9% of patients overall, with rates rising at higher doses. In adult comparison trials, 14% to 15% of people had diarrhea. In children treated for ear infections, it reached 14% on twice-daily dosing and 34% on three-times-daily dosing.
A small study in healthy volunteers found that amoxicillin-clavulanate changed contraction patterns in the small intestine, which may help explain the extra GI upset. And a 2023 analysis of FDA adverse event reports found diarrhea was reported about twice as disproportionately with amoxicillin-clavulanate as with amoxicillin alone. If you want the full side-by-side, see our guide to how amoxicillin and Augmentin differ.
How long does diarrhea last after amoxicillin?
Ordinary amoxicillin diarrhea usually starts within the first week of treatment, though it can show up later. Once you finish the course, it typically fades over several days as your gut bacteria rebuild. One 2023 review described most cases as mild and self-limiting, often settling within roughly 5 to 10 days of stopping the antibiotic. The amoxicillin and Augmentin labels advise contacting your doctor if diarrhea is severe or lasts more than 2 or 3 days.
Your 3-phase plan
You can’t guarantee you’ll avoid amoxicillin and diarrhea problems, but you can lower the odds and catch trouble early.
Before the first dose
- Tell your prescriber about past antibiotic diarrhea or C. diff. A previous C. diff infection is a known risk factor, and it may change which antibiotic is chosen or how closely you’re followed.
- Ask whether plain amoxicillin will do the job. Sometimes amoxicillin-clavulanate is truly needed. When it isn’t, the narrower drug is usually easier on the stomach. Your prescriber makes that call based on the infection, not on side effects alone.
- Ask about twice-daily dosing. For Augmentin in children, the label notes the every-12-hour schedule causes significantly less diarrhea than every-8-hour dosing. Don’t change your own schedule; ask if it’s an option.
- Decide on a probiotic now, not on day four. Trials that showed benefit generally started the probiotic alongside the antibiotic. Check the scorecard below and the list of people who should skip probiotics.
During the course
- Take doses with food. Both the amoxicillin and Augmentin labels say to take the medicine at the start of a meal to reduce stomach upset. For Augmentin, food also helps your body absorb the clavulanate.
- Keep the schedule steady. Evenly spaced doses keep levels consistent. If you slip up, our guide on what to do after a missed amoxicillin dose explains the usual approach. Never double up to “catch up” unless your pharmacist tells you to.
- Drink more than usual. Even mild loose stools pull water and salts out of your body. Sip fluids through the day instead of chugging at once.
- Go easy on alcohol, caffeine, and very greasy or sugary foods. These can make loose stools worse. Moderate drinking doesn’t directly interact with amoxicillin, but it can irritate an already unsettled gut; see our post on drinking while taking amoxicillin.
- Don’t stop the antibiotic on your own. Mild diarrhea is usually not a reason to quit. Call your prescriber instead; they may keep you on it, switch drugs, or check for C. diff.
- Skip anti-diarrhea medicine unless a clinician says it’s OK. Drugs like loperamide (Imodium) slow the gut, which can be a problem if C. diff is involved.
Using hormonal birth control? Diarrhea can matter more than the antibiotic itself. Frequent, severe diarrhea within a few hours of taking the pill may reduce absorption. Our article on amoxicillin and birth control walks through when backup contraception makes sense.
After the last dose
- Expect gradual improvement. Stools often firm up over several days. Return to your normal diet step by step rather than all at once.
- Continue a probiotic briefly if you’re using one. Many trials continued probiotics for a short time after the antibiotic ended. There’s no fixed standard, so ask your pharmacist how long makes sense for your product.
- Feed your gut bacteria. Once you’re tolerating food, fiber from oats, beans, vegetables, and fruit supports the species that help your gut recover.
- Stay alert for weeks, not days. C. diff can start long after your last pill. According to the FDA labeling, cases have surfaced as late as two months or more after the last dose. If watery diarrhea starts up again, mention your recent amoxicillin to whoever you see.
- Toss any leftover pills properly. Saving antibiotics “for next time” leads to wrong-drug, wrong-dose use, and each unnecessary course raises your C. diff risk again.
Probiotics with amoxicillin: the evidence scorecard
Probiotics are live microbes meant to support your gut while the antibiotic does its job. The research is more encouraging than many people expect, but results depend heavily on the strain and the dose. “Probiotic” on a label tells you very little; the specific strain name tells you much more.
What the major reviews and guidelines say
Children (Cochrane, 2019). A Cochrane review of probiotics for preventing antibiotic diarrhea in children pooled 33 trials with 6,352 kids. Diarrhea occurred in 8% of children taking probiotics versus 19% of those who didn’t. That works out to roughly one case prevented for every 9 children treated. The benefit concentrated in high-dose products of at least 5 billion colony-forming units (CFU) a day, where the rate fell from 23% to 8%. Low-dose products showed no clear benefit. The authors singled out Lactobacillus rhamnosus and Saccharomyces boulardii at 5 to 40 billion CFU a day as the most appropriate choices, while noting a large confirmatory trial is still needed.
C. diff prevention (Cochrane, 2017). A separate Cochrane review of probiotics for preventing C. difficile diarrhea in adults and children included 31 trials with 8,672 people. Probiotics cut the risk of C. diff diarrhea by about 60% overall. The clearest benefit appeared in groups whose starting risk was above 5%, often hospitalized patients. In lower-risk groups, the effect was uncertain.
AGA guideline (2020). The American Gastroenterological Association made a conditional suggestion, based on low-quality evidence, for certain probiotics to prevent C. diff in people taking antibiotics. Its named options were S. boulardii; a two-strain mix of L. acidophilus CL1285 and L. casei LBC80R; and two specific three- and four-strain mixes containing L. acidophilus, L. delbrueckii subsp. bulgaricus, and Bifidobacterium bifidum (the four-strain version adds Streptococcus salivarius subsp. thermophilus). The AGA also said it’s reasonable to skip probiotics if you’re more concerned about cost or possible harms, especially as an outpatient where C. diff risk is low.
The scorecard
The ratings below are our summary of the evidence above, meant to help you have a sharper conversation with your pharmacist. They aren’t an official grading system.
| Option | Evidence for preventing antibiotic diarrhea | Dose range used in studies | Our rating | Notes |
|---|---|---|---|---|
| Lactobacillus rhamnosus GG (LGG) | Named as a top choice in the 2019 Cochrane pediatric review; recommended for AAD prevention in at least one guideline reviewed by Canada’s CADTH | 5–40 billion CFU/day (pediatric review range) | Strong for kids; good for adults | Widely available; check the label for the “GG” strain designation |
| Saccharomyces boulardii | Named in the 2019 Cochrane pediatric review; included in AGA 2020 options for C. diff prevention | 5–40 billion CFU/day (pediatric review range) | Strong | A yeast, not a bacterium, so amoxicillin doesn’t kill it; avoid if you have a central line or weak immune system |
| Specific multi-strain products | Certain defined combinations are named in the AGA 2020 guideline for C. diff prevention | Varies by product | Moderate, product-specific | Only the exact combinations studied carry this evidence; a random “10-strain blend” does not |
| Yogurt and kefir | Not the focus of the Cochrane reviews; live-culture counts and strains vary and are often not stated | Usually unknown | Weak (as prevention) | Fine as food if dairy sits well with you; just don’t count on it as your probiotic dose |
So what’s the best probiotic for antibiotic diarrhea?
Based on current evidence, the strongest candidates are an LGG product or an S. boulardii product that delivers at least 5 billion CFU a day, or one of the specific multi-strain formulas named by the AGA. Look for the full strain name on the label, a CFU count guaranteed through the expiration date (not just “at time of manufacture”), and third-party testing if you can find it. Dietary supplements aren’t reviewed by the FDA for effectiveness before they’re sold, so quality varies.
Timing: should you space probiotics from amoxicillin?
Here’s where honest labeling matters. A common pharmacy tip is to take a bacterial probiotic (like LGG) about two hours before or after your amoxicillin dose, on the idea that the antibiotic could kill some of the bacteria if they meet in your stomach at the same time. That makes biological sense, but it’s common advice, not something trials have proven. The studies in the Cochrane reviews used varied schedules.
S. boulardii is a yeast, and amoxicillin doesn’t act on yeasts, so spacing is less of a concern with it. Starting on day one and staying consistent likely matters more than the exact hour.
Who should avoid probiotics
For healthy people, probiotics in trials caused few side effects, mostly gas, bloating, or mild stomach upset. But live microbes can, rarely, enter the bloodstream and cause serious infection in vulnerable people. The Cochrane pediatric review flagged reports of serious harm in severely debilitated or immunocompromised children, especially those with central venous catheters. Talk with your doctor before using any probiotic if you or your child:
- Has a weakened immune system (chemotherapy, organ transplant, advanced HIV, high-dose steroids or other immune-suppressing drugs)
- Has a central line, port, or other long-term IV catheter
- Is critically ill, severely debilitated, or recovering from major bowel surgery
- Is a premature baby
That last point is backed by a specific FDA warning. In fall 2023 the agency alerted health care providers that preterm infants given probiotics can develop invasive, potentially fatal infections, citing the death of a preterm baby from sepsis linked to a Bifidobacterium longum probiotic. The FDA has not approved any probiotic as a drug for use in infants. If you’re pregnant, most common probiotics are generally considered low risk, but check with your obstetric provider; our guide to taking amoxicillin during pregnancy covers the antibiotic side of things.
What to eat and drink on antibiotics
For decades, the go-to advice for diarrhea was the BRAT diet: bananas, rice, applesauce, and toast. Those foods are gentle, and there’s nothing wrong with them. The problem is that BRAT alone is low in protein, fat, and overall nutrition. Current guidance, including MedlinePlus advice on diarrhea in children, leans toward continuing to eat normally when possible, choosing bland foods if they help, and eating smaller meals more often.
Hydration matters more than any single food. Water alone replaces fluid but not the sodium and potassium you lose in stool, and drinking large amounts of plain water by itself isn’t ideal. An oral rehydration solution (such as Pedialyte or a store brand) is designed with the right balance of salt and sugar to help your gut absorb fluid. Broth and salty crackers also help replace sodium.
| Category | Good choices | Limit or avoid for now |
|---|---|---|
| Drinks | Oral rehydration solution, water alongside salty foods, clear broth, diluted juice | Full-strength apple and other fruit juices, soda, energy drinks, coffee and caffeinated tea, alcohol |
| Starches | White rice, plain pasta, oatmeal, white toast, crackers, pretzels, baked potato | Very sugary cereals and pastries |
| Proteins | Eggs, baked or broiled chicken, turkey, fish, tofu | Fried, fatty, or heavily spiced meats |
| Fruits and vegetables | Bananas, applesauce, well-cooked carrots and squash without skins or seeds | Large raw salads, prunes, foods that make you gassy (cabbage, broccoli) until you settle |
| Dairy | Low-fat yogurt or small amounts of milk if tolerated | Large servings of milk or ice cream if they worsen cramps, gas, or bloating |
| Sweeteners | Small amounts of regular sugar or honey (not for babies under 1) | Sugar-free gum and candy with sorbitol, xylitol, or mannitol |
A tip many people miss: some chewable Augmentin tablets contain mannitol, a sugar alcohol. The label notes it’s not known whether its pediatric diarrhea data apply to the chewables, which contain mannitol. If you notice more GI upset with chewables, ask your pharmacist whether the liquid suspension is an option.
Kids and diarrhea on amoxicillin
Children get amoxicillin more than almost any other antibiotic, often for ear infections, and they’re also more prone to antibiotic diarrhea. Our guide to amoxicillin for children’s ear infections covers dosing and duration. Here’s how to handle the stool side of things.
Watch for dehydration
Small bodies lose fluid quickly. MedlinePlus lists these warning signs that mean you should contact your child’s provider:
- Much less active than usual, not sitting up or looking around
- Sunken eyes
- Dry, sticky mouth
- No tears when crying
- No urine for 6 hours (or very few wet diapers)
Keep breastfeeding or formula feeding as usual. For toddlers and older kids, offer small, frequent sips of an oral rehydration solution. Avoid full-strength juice and soda, which can make diarrhea worse.
Diaper rash and yeast
Frequent loose stools irritate skin fast. Change diapers promptly, rinse with lukewarm water or fragrance-free wipes, pat dry, and apply a thick layer of zinc oxide or petroleum barrier cream. Antibiotics can also let yeast grow, which tends to look like an angry red patch ringed by tiny “satellite” dots, usually tucked into skin creases. If the rash doesn’t improve with barrier cream in a couple of days, ask your pediatrician; a yeast rash usually needs an antifungal cream.
A diaper rash isn’t the same as an allergic rash. Hives, swelling, or a widespread rash on the body are a different issue, covered in our article on amoxicillin’s side effects.
When to call the pediatrician
- Any dehydration sign listed above
- Blood or mucus in the stool
- Fever that doesn’t go away, or a new fever after the original one had cleared
- Ongoing belly pain, or a swollen, tender belly
- Vomiting that keeps your child from holding down the antibiotic or fluids
- Diarrhea that’s severe or lasts more than 2 or 3 days
Don’t give children anti-diarrhea medicine without talking to their provider first. MedlinePlus advises against giving medicine to slow diarrhea without first checking with a provider, and that includes over-the-counter products marketed for upset stomachs.
Is it C. diff after amoxicillin?
C. diff is a bacterium that can live quietly in the gut or be picked up from contaminated surfaces. When antibiotics clear out its competition, it can multiply and release toxins that inflame the colon. The CDC’s guide to recognizing C. diff at home notes that people are 7 to 10 times more likely to get C. diff while taking antibiotics and in the month afterward. Its listed risk factors include age 65 or older, a recent hospital stay, a weakened immune system, and a previous C. diff infection.
Amoxicillin isn’t the highest-risk antibiotic for C. diff, but any antibiotic can trigger it, and amoxicillin is prescribed so often that it shows up in plenty of cases. The table below compares ordinary antibiotic diarrhea with patterns that should make you think of C. diff.
| Feature | Ordinary antibiotic diarrhea | Possible C. diff |
|---|---|---|
| Stool frequency | A few loose stools a day | Watery diarrhea 3 or more times a day for more than a day; severe cases can reach 10–15 a day |
| Fever | Usually none | Often present, especially a new fever |
| Belly pain | Mild cramping, if any | Cramping, tenderness, or severe pain; possible swelling |
| Blood or pus | Not expected | Can occur |
| Other symptoms | Feel mostly OK | Nausea, loss of appetite, dehydration, fast heart rate |
| Timing | During the course; fades within days of stopping | Often starts 5–10 days into treatment, but can begin after the course ends, even 2 months or more later |
| Who’s at higher risk | Anyone on antibiotics, especially amoxicillin-clavulanate | Age 65+, recent hospitalization, weak immune system, prior C. diff |
According to Mayo Clinic’s overview of C. difficile infection, symptoms usually start 5 to 10 days after beginning an antibiotic but can appear as early as the first day or up to three months later. That long window is why you should always tell a clinician about recent antibiotic use, even if you finished weeks ago.
Why not just take Imodium? Medicines that slow the gut, like loperamide, can hold toxins in the colon longer if C. diff is the cause. Check with a clinician before using any anti-diarrhea medicine during or after an antibiotic. If C. diff is confirmed, it’s treated with specific antibiotics, and your prescriber will usually stop the original antibiotic if possible.
When to call vs. go to the ER
Manage at home and keep watching
- A few loose stools a day, no fever, no blood
- You’re drinking and urinating normally
- You otherwise feel well and the infection is improving
Call your doctor or pharmacist (same day)
- Three or more watery stools a day, or diarrhea lasting more than 2 to 3 days
- A new fever, or belly cramps that keep coming back
- Watery diarrhea that starts days or weeks after you finished amoxicillin
- Diarrhea bad enough that you’re thinking about stopping the antibiotic
- You’re 65 or older, pregnant, immunocompromised, or have had C. diff before
- A child showing early signs of dehydration
Go to the ER or call 911
- Blood or pus in the stool, or black, tarry stools
- Severe belly pain, or a swollen, hard belly
- Signs of serious dehydration: dizziness or fainting when standing, very little or no urine, confusion, a racing heart
- A baby or young child who is unusually sleepy, hard to wake, or has had no wet diaper in many hours
- High fever with severe diarrhea, or 10 or more watery stools a day
- Trouble breathing, swelling of the face or throat, or widespread hives (possible allergic reaction)
Frequently asked questions
Should I stop taking amoxicillin if I get diarrhea?
Not on your own. Mild diarrhea is a known side effect and usually isn’t a reason to stop, and quitting early can leave the infection undertreated. Call your prescriber if diarrhea is severe, watery several times a day, bloody, or comes with fever. They may keep you on amoxicillin, switch you, or test for C. diff.
Can I take probiotics at the same time as amoxicillin?
Many people do, and the trials showing benefit started probiotics alongside the antibiotic. Spacing a bacterial probiotic about two hours from your amoxicillin dose is common advice, though it hasn’t been proven in trials. S. boulardii, a yeast, isn’t affected by amoxicillin. Skip probiotics and ask your doctor first if you’re immunocompromised, have a central line, or are caring for a premature baby.
Is yogurt enough to prevent antibiotic diarrhea?
Probably not by itself. Most yogurts don’t list the strain or a guaranteed live-culture count, and the strong evidence comes from specific supplement strains at doses of 5 billion CFU a day or more. Yogurt is a fine food choice if dairy agrees with you, but it isn’t a reliable stand-in for a studied probiotic.
Does Augmentin cause more diarrhea than amoxicillin?
Yes, generally. The clavulanate in Augmentin adds GI side effects, and diarrhea is the most common reaction on its label. Taking it at the start of a meal helps, and in children, twice-daily dosing caused much less diarrhea than three-times-daily dosing in the label’s trials.
Can C. diff start after I finish amoxicillin?
Yes. The FDA labels note C. diff diarrhea has been reported more than 2 months after antibiotic treatment, and Mayo Clinic says it can appear up to three months later. If you develop frequent watery diarrhea, fever, or belly pain in the weeks after a course, tell your doctor you recently took amoxicillin.
Medical disclaimer: Nothing here replaces a conversation with your own clinician or pharmacist, especially before giving probiotics to a baby or someone with a weak immune system. Always follow your prescription label and your prescriber’s directions, and ask before starting, stopping, or changing any medicine or supplement. If you think you or your child is having a medical emergency, call 911 or go to the nearest emergency room.
References
- U.S. Food and Drug Administration. Amoxicillin capsules, tablets, and for oral suspension: prescribing information. FDALabel.
- U.S. Food and Drug Administration. Augmentin (amoxicillin/clavulanate potassium) prescribing information. 2022.
- Guo Q, Goldenberg JZ, Humphrey C, El Dib R, Johnston BC. Probiotics for the prevention of pediatric antibiotic-associated diarrhea. Cochrane Database of Systematic Reviews. 2019.
- Goldenberg JZ, Yap C, Lytvyn L, et al. Probiotics for the prevention of Clostridium difficile-associated diarrhea in adults and children. Cochrane Database of Systematic Reviews. 2017.
- Su GL, Ko CW, Bercik P, et al. AGA Clinical Practice Guidelines on the Role of Probiotics in the Management of Gastrointestinal Disorders. Gastroenterology. 2020.
- U.S. Food and Drug Administration. Risk of invasive disease in preterm infants given probiotics formulated to contain live bacteria or yeast. 2023.
- Centers for Disease Control and Prevention. Recognizing C. diff at home.
- Mayo Clinic. C. difficile infection: symptoms and causes.
- MedlinePlus, U.S. National Library of Medicine. When your child has diarrhea.
- Huang H, Li L, Wu M, et al. Antibiotics and antibiotic-associated diarrhea: a real-world disproportionality study of the FDA adverse event reporting system from 2004 to 2022. BMC Pharmacology and Toxicology. 2023.
- CADTH. Probiotics for Antibiotic-Associated Diarrhea and Clostridium difficile Infection: A Review of Guidelines. 2018.
