Antibiotics & Gut Health: Why Every Pet Needs Probiotic Support During and After Treatment

Antibiotics have transformed modern medicine and have saved countless lives—both human and animal. They are invaluable when treating bacterial infections, but they also come with an often-overlooked consequence: they don't discriminate between harmful bacteria and the beneficial microbes that make up the gut microbiome.

This is why supporting the gut during and after antibiotic treatment is so important.

The Hidden Cost of Antibiotics

The gut is home to trillions of beneficial microorganisms that help:

• Digest food and absorb nutrients.

• Support immune function.

• Produce essential vitamins.

• Protect against harmful pathogens.

• Maintain healthy digestion.

When antibiotics are prescribed, they eliminate disease-causing bacteria—but they also reduce many of these beneficial microbes. This disruption, known as dysbiosis, can leave the gut vulnerable long after the antibiotic course has finished.

Common signs of an imbalanced microbiome include:

• Loose stools or diarrhoea.

• Digestive upset.

• Reduced appetite.

• Reduced immune resilience.

However, one of the biggest concerns after antibiotic use is opportunistic yeast overgrowth.

In addition to increasing the risk of digestive upset, antibiotics can significantly reduce the diversity of beneficial bacteria that make up the gut microbiome. A recent 2025 peer-reviewed study using a canine gut model demonstrated just how profoundly antibiotics can disrupt the gut ecosystem. Researchers found that antibiotic exposure significantly reduced microbial diversity and altered the balance of beneficial bacteria within the model, reinforcing the importance of supporting gut health during and after antibiotic treatment.

Antibiotics Can Create the Perfect Environment for Yeast

Healthy bacteria help keep naturally occurring yeasts in check. When antibiotics dramatically reduce these beneficial bacteria, yeasts such as Candida can seize the opportunity to multiply.

This imbalance can contribute to yeast-related issues including:

• Persistent itchy skin.
• Recurring ear infections.
• Paw licking.
• Unpleasant odour.
• Digestive upset.
• Ongoing microbiome imbalance.

While antibiotics don't directly cause yeast infections, they can create the conditions that allow yeast to flourish—particularly after repeated or long-term antibiotic use or in pets already prone to yeast issues.

Supporting the microbiome after antibiotics is one of the best ways to help restore the natural balance between beneficial bacteria and yeast.

Why Probiotics Should Always Follow Antibiotics

Once an antibiotic course has finished, replenishing the gut with a high-quality, multi-strain probiotic can help restore microbial diversity—the wide range of beneficial bacteria that contributes to a healthy, resilient gut.

Not all probiotics are created equal.

When choosing a probiotic, look for one that contains:

• Multiple clinically researched strains rather than just one or two.

• A meaningful number of live organisms (CFUs).

• Strains that have been selected to work together to support digestive and immune health.

• High-quality manufacturing that helps ensure the bacteria remain viable until they reach the gut.

Different probiotic strains perform different jobs. Some are better at supporting digestion, others help maintain the intestinal barrier, while others play an important role in immune function. A diverse probiotic provides broader support for rebuilding a healthy microbiome.

That's why we chose an evidence-backed, veterinary-formulated probiotic containing seven carefully selected strains, providing comprehensive support for microbiome recovery after antibiotics and helping to restore healthy bacterial diversity.

The Exception: Saccharomyces Boulardii

One probiotic stands out from the rest—Saccharomyces boulardii (often abbreviated to S. boulardii or SB).

Unlike most probiotics, Saccharomyces boulardii is a beneficial yeast, not a bacterium. Because antibiotics target bacteria—not yeast—SB is unaffected by antibiotic therapy and can be taken throughout the course of treatment.

This unique characteristic makes it an excellent choice for supporting gut health while antibiotics are working.

Exciting new veterinary research is beginning to demonstrate just how valuable this may be. In a 2025 peer-reviewed study using a canine gut model, researchers found that antibiotic exposure significantly reduced microbial diversity and altered the balance of beneficial bacteria within the model. Treatment with Saccharomyces boulardii supported recovery of the gut microbiome following this antibiotic-induced disruption, adding to the growing body of evidence supporting SB as part of a comprehensive gut health strategy.

Research has shown that Saccharomyces boulardii may help:

• Reduce the risk of antibiotic-associated diarrhoea.

• Support normal bowel function during antibiotic use.

• Help maintain a healthier gut environment.

• Support the gut's natural protective barrier.

For pets requiring repeated or long-term courses of antibiotics, Saccharomyces boulardii is particularly valuable because it helps support the gut while beneficial bacterial populations are being depleted.

The Best Strategy

Current research suggests that supporting the microbiome both during and after antibiotic therapy provides the best opportunity to minimise gut disruption and promote recovery.

During antibiotics

Support the gut with Saccharomyces boulardii throughout the antibiotic course to help reduce the risk of antibiotic-associated diarrhoea and maintain a healthier gut environment.

If you also choose to use a bacterial probiotic during treatment, administer it at least 2–3 hours apart from the antibiotic (unless your veterinarian advises otherwise).

After antibiotics

Once the antibiotic course is complete, the focus shifts to rebuilding the gut microbiome.

This is where a high-quality, multi-strain probiotic becomes essential.

Our APN 7-Strain Probiotic was formulated with microbial diversity in mind, providing broad-spectrum support to help restore beneficial bacteria after antibiotic therapy and encourage a healthier, more resilient microbiome.

For best results, continue a quality multi-strain probiotic for at least 4–8 weeks after completing antibiotics, or longer following repeated or long-term antibiotic use.

For Pets Requiring Repeated or Long-Term Antibiotics

Repeated antibiotic courses can make it increasingly difficult for the gut microbiome to recover fully. Each course may further reduce microbial diversity, increasing the likelihood of persistent dysbiosis and creating an environment where opportunistic yeasts, such as Candida, can become more established.

For these pets, a sensible strategy is to:

• Continue Saccharomyces boulardii throughout the antibiotic course.

• Begin a quality 7-strain probiotic once antibiotics are finished to help restore beneficial bacteria and microbial diversity.

• In some cases, continue both products together during the recovery period, under veterinary guidance.

Quick Recovery Checklist

✔ Give antibiotics exactly as prescribed by your veterinarian.

✔ Support the gut during treatment with Saccharomyces boulardii.

✔ Follow antibiotics with a high-quality 7-strain probiotic for at least 4–8 weeks to help restore microbial diversity.

✔ For pets requiring repeated antibiotic courses, speak with your veterinarian about ongoing probiotic support.

Protect the Microbiome—Don't Just Treat the Infection

Antibiotics are often essential and can be life-saving, but treating the infection is only part of the recovery process.

Supporting the microbiome helps restore the beneficial bacteria that play an important role in digestion, immune health and skin health. It may also help reduce the risk of opportunistic yeast overgrowth, such as Candida, that can occur when healthy bacterial populations have been depleted.

Whenever antibiotics are needed, remember the recovery plan:

✔ During antibiotics: Support the gut with Saccharomyces boulardii.

✔ After antibiotics: Restore microbial diversity with a high-quality 7-strain probiotic for at least 4–8 weeks.

✔ For repeated or long-term antibiotic use: Continue Saccharomyces boulardii throughout treatment, then follow with your multi-strain probiotic—or use both during recovery if recommended by your veterinarian.

As our understanding of the canine microbiome continues to grow, so too does the evidence supporting proactive gut care. Recent research confirms that restoring microbial diversity after antibiotics is an important part of recovery—not simply an optional extra. Supporting the microbiome during treatment with Saccharomyces boulardii, followed by a quality multi-strain probiotic afterwards, gives your pet the best opportunity to recover from infection while protecting the long-term health of their gut.

The information in this article is based on published scientific research and is intended for educational purposes only. It is not a substitute for veterinary advice. Always consult your veterinarian before starting supplements or making changes to your pet's treatment plan.

References

Deschamps C, et al. (2025). Lactobacillus helveticus-derived postbiotic and live Saccharomyces boulardii restore gut microbiota after antibiotic disturbance in an in vitro canine gut model. Beneficial Microbes.

Dethlefsen L, Relman DA. (2011). Incomplete recovery and individualized responses of the human distal gut microbiota to repeated antibiotic perturbation. Proceedings of the National Academy of Sciences.

Langdon A, Crook N, Dantas G. (2016). The effects of antibiotics on the microbiome throughout development and alternative approaches for therapeutic modulation. Genome Medicine.

Hempel S, et al. (2012). Probiotics for the prevention and treatment of antibiotic-associated diarrhoea: A systematic review and meta-analysis. JAMA.

Szajewska H, Kołodziej M. (2015). Systematic review: Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea. Alimentary Pharmacology & Therapeutics.

McFarland LV. (2010). Systematic review and meta-analysis of Saccharomyces boulardii. World Journal of Gastroenterology.

Pappas PG, et al. (2016). Clinical Practice Guideline for the Management of Candidiasis. Clinical Infectious Diseases.

Guard BC, et al. (2015). Characterization of the faecal microbiome during and after antibiotic treatment in healthy dogs.

Weese JS, et al. (2011). ACVIM Consensus Statement on Probiotics for Dogs and Cats. Journal of Veterinary Internal Medicine.

Chapman CMC, Gibson GR, Rowland I. (2011). Health benefits of probiotics: Are mixtures more effective than single strains? European Journal of Nutrition.