PROBIO Journal · Gut & microbiome
Rebuilding your gut flora after antibiotics: what to eat, how long it takes and the 4-week plan
The antibiotics are finished, but your stomach is still rumbling? That is normal, because antibiotics affect not only the bacteria that cause illness, but also many beneficial gut bacteria.
Antibiotics are often indispensable for bacterial infections. At the same time, they disrupt the gut flora (the gut microbiome): the diversity of gut bacteria decreases, and many people get diarrhoea, wind or a sensitive stomach. In this guide you will learn what antibiotics do in the gut, how long the gut flora takes to recover after antibiotics, what you should eat during and after the course, what role probiotics play and how to rebuild your gut flora step by step over four weeks after antibiotics.
What do antibiotics do to the gut flora?
Trillions of bacteria from hundreds of different species live in your gut. Antibiotics do not distinguish between “good” and “bad” bacteria. They act against the pathogen causing the infection, but also against many beneficial gut bacteria. The result: the diversity of the gut flora often decreases considerably while you are taking antibiotics.
How strongly the gut flora is affected depends on the antibiotic, how long it is taken and how diverse your microbiome was beforehand. Broad-spectrum antibiotics, which act against a very large number of bacterial species, affect the gut flora more strongly than targeted antibiotics.
Typical symptoms after antibiotics
- soft stools or diarrhoea (antibiotic-associated diarrhoea)
- wind and a feeling of fullness, read more in Bloating and feeling full
- rumbling stomach and sensitive stomach
- changing digestion, sometimes also constipation, see Constipation: what helps quickly?
- in women, vaginal yeast infections are more common, because the bacterial flora there is also disrupted
How long does the gut flora take to recover after antibiotics?
The good news: in most healthy people, the gut flora recovers on its own after antibiotics. Studies show that a large part of the bacterial community levels out again within about one to two months. Individual bacterial species take longer, and some studies still observe changes after six months.
| Time after antibiotics | What happens in the gut (guide values) |
|---|---|
| first few days | digestion often still unsettled, diarrhoea usually subsides |
| 2 to 4 weeks | bacterial diversity increases again, symptoms become less frequent |
| 1 to 2 months | in many people the gut flora has largely recovered |
| up to 6 months | individual bacterial species are still returning |
Guide values for orientation. How quickly your gut flora recovers is individual.
You can help influence how quickly your gut flora rebuilds after antibiotics: above all, a high-fibre, varied diet provides food for the beneficial gut bacteria.
While taking antibiotics: what to look out for
- Take exactly as prescribed: Take the antibiotic at the prescribed dose and for the prescribed duration, and do not stop it on your own.
- Keep a gap from milk and minerals: Some antibiotics, for example tetracyclines and quinolones, are absorbed less well together with dairy products, calcium, magnesium, iron or zinc. Ask your pharmacist about the right interval; it is often 2 to 3 hours.
- No alcohol: With some antibiotics, such as metronidazole, alcohol can cause a severe intolerance reaction. It also puts additional strain on the gut.
- Drink plenty, especially if you have diarrhoea: Water, herbal tea, clear broth.
- Eat light: Cooked, mild meals are now often easier to tolerate than large portions of raw vegetables.
What to eat after antibiotics? Foods for the gut flora
Your gut bacteria live on what you eat. For the gut flora to rebuild after antibiotics, it needs above all fibre, and as many different types as possible.
| Food group | Examples | Why it is good for the gut flora |
|---|---|---|
| Soluble fibre | Rolled oats, cooked carrots, apples, linseed | gentle, easy to tolerate, food for gut bacteria |
| Prebiotic foods | Chicory, parsnips, Jerusalem artichoke, leeks, onions, slightly green bananas | contain inulin, oligofructose or resistant starch |
| Cooled starch | Day-old potatoes, rice or pasta | resistant starch forms as they cool |
| Fermented foods | Natural yoghurt, kefir, sauerkraut, kimchi | contain live cultures if not heated |
| A variety of plants | Vegetables, fruit, herbs, nuts, pulses | the more plant species, the more diverse the microbiome |
To see which foods provide how much fibre, take a look at our Fibre table with daily requirement and the best foods.
What you should rather avoid after antibiotics
- very fatty, fried foods
- lots of sugar and highly processed foods, as they promote a one-sided gut flora
- Alcohol
- large portions of raw vegetables and pulses in the first few days, as this often causes bloating
Does yoghurt help after antibiotics?
Natural yoghurt and kefir contain live lactic acid bacteria and are well tolerated by many people. They are a good building block, but do not replace the fibre that your own gut bacteria need to grow. While taking antibiotics, keep a gap between them and the medicine if the antibiotic must not be taken with milk.
Rebuilding your gut flora after antibiotics: the 4-week plan
| Period | Focus | In practice |
|---|---|---|
| Week 1 | Calm | Cooked, mild food: porridge, rice, potatoes, steamed vegetables, soups. Drink plenty. Natural yoghurt or kefir if tolerated. |
| Week 2 | Start with fibre | Rolled oats every day, 1 tbsp ground linseed, cooked carrots or parsnips. Cooled potatoes or rice. |
| Week 3 | Increase variety | Small portions of pulses, wholegrains, sauerkraut, more fruit and vegetables. Goal: 20 different plants per week. |
| Week 4 | Consolidate the routine | Continue increasing raw vegetables and pulses, towards 30 g of fibre a day. Eat regularly, exercise daily, sleep well. |
Increase fibre by about 5 g per week. If you eat too much too quickly, you will get wind. To find out how to maintain a diverse gut flora in the long term afterwards, read our guide Building up your gut flora: how to strengthen your gut microbiome in 3 phases.
Probiotics after antibiotics: worthwhile or not?
Probiotics contain live microorganisms, usually lactic acid bacteria and bifidobacteria. Whether probiotics help rebuild the gut flora after antibiotics is the subject of intensive research. The results differ depending on the bacterial strain, dose and person, and to date there are no authorised health claims for probiotics in the EU.
Pharmacies offer special preparations for diarrhoea during antibiotic treatment. It is best to discuss whether one of these is suitable for you directly at the pharmacy or with the doctor who prescribed the antibiotic. Important: take preparations containing bacteria 2 to 3 hours apart from the antibiotic.
Regardless of this, the foundation for a diverse gut flora is diet. To find out what role probiotics can play in a daily gut routine, read Building up your gut flora.
What about gut cleanses and gut cures?
There is no good evidence for a “gut cleanse” after antibiotics with colonic irrigation or special cures. Your gut does not need cleansing, but time, fibre and variety.
Diarrhoea after antibiotics: when to see a doctor?
Mild diarrhoea during or shortly after taking antibiotics is common and usually subsides on its own. Contact your doctor if:
- the diarrhoea is very severe, lasts more than three days or only starts days to weeks after the antibiotic
- there is blood or mucus in the stool
- you have a fever or severe abdominal cramps
- you notice signs of dehydration: severe thirst, little urine, dizziness
- you are older, chronically ill or pregnant
Severe, watery diarrhoea after antibiotics may be caused by an infection with the bacterium Clostridioides difficile, which must be treated by a doctor. Do not take anti-diarrhoeal medicines without medical advice.
Frequently asked questions
How long does it take for the gut flora to recover after antibiotics?
In most healthy people, the gut flora has largely recovered after about one to two months. Individual bacterial species take longer, in some cases up to six months.
How can I rebuild my gut flora after antibiotics?
Above all with a high-fibre, varied diet: rolled oats, vegetables, fruit, pulses, wholegrains and fermented foods. Increase fibre slowly, drink enough and exercise every day.
What should you eat after antibiotics?
In the first few days, mild, cooked food such as porridge, rice, potatoes and steamed vegetables. After that, gradually more fibre, prebiotic foods such as chicory or parsnips, and fermented foods such as natural yoghurt, kefir or sauerkraut.
Do probiotics help after antibiotics?
This is the subject of intensive research, and the results depend heavily on the bacterial strain. There are no authorised health claims for probiotics in the EU. For diarrhoea while taking antibiotics, it is best to seek advice at a pharmacy.
Is yoghurt good after antibiotics?
Natural yoghurt and kefir contain live lactic acid bacteria and are well tolerated by many people. However, while taking certain antibiotics you should keep a gap of 2 to 3 hours from dairy products.
Why do antibiotics cause diarrhoea?
Antibiotics also act against beneficial gut bacteria. This throws the gut flora off balance, and digestion becomes unsettled. The diarrhoea usually subsides after the course has ended.
Can you take antibiotics with milk?
That depends on the active substance. Some antibiotics, such as tetracyclines and quinolones, are absorbed less well with milk, calcium or magnesium. Ask your pharmacist.
Do you need a gut cleanse after antibiotics?
No. There is no good evidence for colonic irrigation or special gut cures. The gut flora recovers best with time, fibre and a varied diet.
Can you take antibiotics and probiotics at the same time?
If you do, keep a gap of 2 to 3 hours so that the antibiotic does not directly attack the bacteria. It is best to discuss this with your pharmacist.
When should I see a doctor about diarrhoea after antibiotics?
If you have severe diarrhoea for more than three days, blood or mucus in the stool, fever, severe abdominal cramps, signs of dehydration, or if the diarrhoea only starts days to weeks after the antibiotic.
From the PROBIO range
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PROBIOTIC-13 contains 13 bacterial strains with 6 billion CFU per daily serving, plus inulin from chicory and calcium.
What it includes: 13 individually named strains, 6 billion CFU per day, inulin and gastro-resistant capsules that need no refrigeration.
- Calcium contributes to the normal function of digestive enzymes.
- 2 capsules daily, 60 capsules last 30 days
- Vegan, halal and kosher
Food supplements are not medicines and are not intended to treat the complaints described in this article. Always have symptoms checked by a doctor.
Read more in the PROBIO Journal
- Building up your gut flora: how to strengthen your gut microbiome in 3 phases
- Fibre and prebiotics: table, daily requirement and the best foods
- Bloating and feeling of fullness: causes and what helps
- Constipation: what helps quickly?
- Quality at PROBIO: raw materials, forms and bioavailability
This article is for general information only and does not replace medical advice, diagnosis or treatment. Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle.