What is the best probiotic to take while on antibiotics? A Comprehensive Guide

October 6, 2025 •

5 min read

Studies show that as many as one in three people taking antibiotics may experience antibiotic-associated diarrhea. Taking the right probiotic alongside your medication is a research-backed strategy to help maintain gut balance and reduce unwanted side effects, making it crucial to know what is the best probiotic to take while on antibiotics?.

Quick Summary

Antibiotics disrupt the gut microbiome, leading to potential side effects like diarrhea. Certain probiotic strains, such as Saccharomyces boulardii and Lactobacillus rhamnosus GG, have strong evidence for minimizing these disturbances. Proper timing, starting at the beginning of treatment, and consuming for weeks after are key for gut health.

Key Points

Saccharomyces boulardii and Lactobacillus rhamnosus GG (LGG) are the most well-researched probiotic strains for use during antibiotic treatment.
Take probiotics at least 2 hours apart from your antibiotic medication to ensure the beneficial bacteria survive, with the exception of the yeast S. boulardii.
Start taking the probiotic on the first day of your antibiotic course and continue for several weeks after finishing the medication.
Prebiotic foods like garlic, onions, and asparagus can help feed and nourish the beneficial bacteria in your gut during recovery.
Fermented foods are great for overall gut health but may not provide a high enough, targeted dose of probiotics to counteract the effects of antibiotics.
Consult your doctor before starting a probiotic, especially if you have a weakened immune system, as there are certain risk factors to consider.

Why taking a probiotic with antibiotics is important

Antibiotics are essential for fighting bacterial infections, but they are a double-edged sword for the human body. These powerful medications are non-discriminatory, killing off not only the pathogenic bacteria causing an illness but also a large number of beneficial bacteria that reside in the gut microbiome. This collateral damage can lead to a state of imbalance, known as dysbiosis, which can result in common gastrointestinal side effects like diarrhea, nausea, and bloating.

Replenishing the gut with beneficial bacteria by taking a probiotic is a proactive strategy to mitigate these effects. By introducing specific, resilient strains, you can help fortify the gut environment and support its return to a healthy, diverse state.

The most effective probiotic strains to take with antibiotics

Research has identified several key probiotic strains that are particularly effective at surviving antibiotic exposure and reducing associated side effects. Selecting a supplement with these specific strains is more beneficial than relying on general probiotic formulas.

Saccharomyces boulardii: This is a friendly, non-pathogenic yeast, not a bacterium, which makes it naturally resistant to antibiotics. This means it can be taken at the same time as antibiotics without being killed. It is one of the most clinically studied probiotics for preventing antibiotic-associated diarrhea (AAD) and has been shown to be effective in both adults and children. It may also be particularly helpful in preventing Clostridioides difficile-related diarrhea.
Lactobacillus rhamnosus GG (LGG): One of the most extensively researched bacterial strains, LGG has proven efficacy in reducing the risk and duration of AAD in both children and adults. It is well-adapted to survive the harsh gut environment and can help maintain the balance of gut flora during and after antibiotic treatment. The brand Culturelle is a well-known product containing this strain.
Multi-strain combinations: Some supplements offer combinations of strains that have been clinically tested together. For example, a combination of Lactobacillus acidophilus Rosell-52, Lactobacillus rhamnosus Rosell-11, and Bifidobacterium lactis Lafti B94 has been shown to survive alongside antibiotics and reduce side effects. Multi-strain products can offer broader support for gut health, but it's important to choose one where the specific combination has been researched.

Timing is critical: How to take your probiotic

When and how you take your probiotic can impact its effectiveness. Here's what you need to know:

Start immediately: Begin taking the probiotic on the same day you start your antibiotic course, not after it's finished. This proactive approach provides the most benefit for protecting your gut.
Maintain a time gap: For most bacterial probiotics, it is recommended to take your probiotic at least 2 hours before or after your antibiotic dose. This separation helps ensure the beneficial bacteria survive and colonize the gut effectively. For the yeast strain Saccharomyces boulardii, however, this separation is not necessary as it is not affected by antibacterial medication.
Continue after antibiotics: Continue taking the probiotic supplement for at least two weeks, and possibly up to a month, after finishing your antibiotic course. This helps to fully replenish the beneficial bacteria and restore microbial diversity.

Comparison of key probiotic strains for antibiotic support


Probiotic Strain	Type	Best For	Timing with Antibiotic	Key Benefits
*Saccharomyces boulardii*	Yeast	Preventing antibiotic-associated and C. difficile diarrhea	Can be taken at the same time as antibiotic.	Naturally resistant to antibacterial drugs; robustly studied for AAD.
*Lactobacillus rhamnosus GG*	Bacteria	Preventing antibiotic-associated diarrhea (AAD) in both adults and children	Take at least 2 hours apart from the antibiotic.	One of the most researched bacterial strains for AAD prevention.
*L. acidophilus Rosell-52, L. rhamnosus Rosell-11 & B. lactis Lafti B94 (combination)*	Bacteria	Reducing gastrointestinal side effects from antibiotics, including nausea and pain.	Can be taken at the same time as the antibiotic.	Clinically tested combination shown to survive alongside antibiotics.

Beyond supplements: Supporting your gut through diet

While supplements provide targeted support, dietary choices play a crucial role in nourishing your gut microbiome and helping it recover post-antibiotic treatment.

Embrace prebiotic foods: Prebiotics are types of fiber that feed the beneficial bacteria in your gut. They are the fuel for your good microbes and can aid in recovery. Great sources include garlic, onions, leeks, asparagus, green bananas, and oats.
Include fermented foods cautiously: Fermented foods like kefir, yogurt, sauerkraut, and kimchi are excellent sources of beneficial bacteria. However, the bacterial strains and dosages in these foods are not standardized. While they are great for general gut health, they are not a reliable substitute for a targeted probiotic supplement during antibiotic use. Always choose products with 'live and active cultures' and minimal added sugar.
Listen to your body: After an antibiotic course, your gut can be sensitive. Going easy on your digestive system with a balanced, whole-food, fiber-rich diet is beneficial for recovery. Minimize processed foods and excessive sugar, which can feed undesirable microbes.

Potential risks and considerations

For most healthy individuals, taking probiotics with antibiotics is considered safe. However, there are some important considerations:

Immunocompromised individuals: People with weakened immune systems, those who are severely debilitated, or with certain health conditions should consult their doctor before taking probiotics. In rare cases, probiotics have caused infections in these populations.
Side effects: While generally mild, some individuals may experience gas, bloating, or abdominal discomfort when starting a probiotic.
Consult your healthcare provider: Always talk to your doctor or pharmacist before starting a new supplement, especially when on medication, to ensure it's appropriate for your health needs.

Conclusion

When facing an antibiotic prescription, being proactive about your gut health is a smart strategy. The answer to what is the best probiotic to take while on antibiotics? points toward well-researched strains like the yeast Saccharomyces boulardii and the bacteria Lactobacillus rhamnosus GG. By starting a targeted probiotic at the same time as your medication, maintaining a two-hour gap (for bacterial strains), and continuing for several weeks after, you can significantly reduce the risk of digestive side effects and support the long-term health of your gut microbiome. For comprehensive recovery, also prioritize a diet rich in prebiotic fiber and fermented foods, all while under the guidance of your healthcare provider.

Frequently Asked Questions

No, not all probiotics are equally effective. It is best to choose specific, clinically studied strains like Saccharomyces boulardii and Lactobacillus rhamnosus GG (LGG), which have been shown to help with antibiotic-associated side effects.

It is generally recommended to continue taking a probiotic for at least two weeks, and potentially for up to a month, after you have finished your antibiotic course. This helps your gut microbiome recover and rebalance.

A time gap of at least two hours is recommended for most bacterial probiotics to prevent the antibiotic from killing the probiotic organisms before they can have a beneficial effect. The yeast strain Saccharomyces boulardii is naturally resistant and does not require this separation.

While fermented foods like yogurt and kefir contain beneficial bacteria, they do not provide the specific strains or high therapeutic doses necessary to effectively counteract the effects of an antibiotic. A high-quality probiotic supplement is more reliable for this purpose.

Probiotics are generally well-tolerated, but some people may experience mild side effects such as gas, bloating, or abdominal discomfort, especially when first starting. These symptoms often subside as your body adjusts.

For most children, it is safe and can be beneficial. However, for severely immunocompromised or critically ill children, there is a small risk of infection. Always consult a pediatrician before giving a child a probiotic.

No, there is no evidence that taking probiotics interferes with the effectiveness of antibiotics. The purpose of taking them is to mitigate the antibiotic's impact on your gut, not to hinder the antibiotic's function.