Your doctor hands over a prescription and talks about finishing every pill. Almost nobody mentions what those pills do to your gut along the way, or what to do about it once the bottle's empty. A short recovery plan changes how fast your gut settles back down, and most people never hear it at the pharmacy counter. If you're just starting a course now rather than finishing one, our starting antibiotics: a simple gut plan covers what to do from day one.
Why antibiotics hit your gut along with the infection
Antibiotics don't aim. They kill bacteria broadly, which clears the infection but also thins out large parts of the bacterial community that normally lives in your digestive tract. A single course can measurably shrink that community's diversity within days.
Most of it grows back on its own. A 2018 study that tracked healthy men through a short course of broad-spectrum antibiotics found their gut bacteria returned to close to normal within about six weeks.[1] But nine species that every man in the study carried before treatment were still missing six months later. Some bacterial residents don't come back without help. For a fuller breakdown of that timeline, see healing your gut after a course of antibiotics, week by week.
The rough stretch right after you finish
The days right after your last pill are when your gut is most exposed. Helpful bacteria are still thinned out, and less helpful species move into that open space fast. This helps explain why diarrhea and stomach upset show up so often around antibiotics, both during the course and right after.
Start a probiotic before you finish the bottle
Probiotics are live bacteria you take as a supplement or get from foods like yogurt. Of everything researchers have studied for antibiotic recovery, this has the strongest track record. In a review of 17 studies covering more than 3,600 people, taking a probiotic alongside antibiotics cut the risk of antibiotic-associated diarrhea by roughly half, though the researchers who conducted the review noted the underlying studies were only moderate quality.[2]
Lactobacillus rhamnosus and Saccharomyces boulardii (a beneficial yeast) are two of the strains most frequently studied and recommended for this use, though evidence quality varies by strain and study.[3] Ask your pharmacist or doctor which product and dose makes sense for you.
What to eat once the course is over
Once you're done, eating a wide range of plants becomes one of the most useful things you can do for your gut. The American Gut Project, a large citizen-science study, found that people eating more than 30 different plant types a week carried noticeably more diverse gut bacteria than people eating 10 or fewer.[4] You don't need to hit 30 this week. Start by adding a few vegetables, beans, or whole grains you don't usually buy, and build from there.
A daily fermented food, yogurt, kefir, sauerkraut, or kimchi, gives your rebuilding bacteria something to work with. Go easy on alcohol and added sugar for a couple of weeks too, and go easy on your gut generally, since what a bad week of eating does to your gut lands harder while it's already rebuilding. Both may make it easier for less helpful bacteria to hold onto the ground they gained while the antibiotic was clearing everything else out.
Save this somewhere you can find it again
Save it as a note on your phone or a screenshot. Antibiotics tend to land right when you feel too rotten to plan a grocery list or work out probiotic timing. Deciding the plan now means you're not figuring it out mid-illness. If you end up on antibiotics often, for recurring infections or anything else, make this recovery routine as automatic as finishing the full bottle already is.
- This content is for educational purposes only and is not a substitute for professional medical advice. Palleja et al., Nature Microbiology, 2018
- NIH National Center for Complementary and Integrative Health
- Cleveland Clinic
- McDonald et al., American Gut Project, mSystems, 2018
