Microbiome Based Medicines: How the UK Now Regulates Them and Where Canada Differs

On 18 August 2026 the MHRA published a position paper confirming that microbiome based medicinal products sit inside the United Kingdom's existing medicines framework. For companies developing live biotherapeutics, faecal microbiota products or engineered microbial therapies, that clarifies the licensing route without waiting for a new regime to be built.

For Canadian developers and their advisers, the more useful question is how this compares with Canada. Here the same bacteria can be a biologic drug, a natural health product, or fall under the faecal microbiota therapy interim policy, depending on the claim and the composition. Getting that classification wrong can cost years.

This article explains what microbiome based medicinal products are, what the MHRA now expects, how Canada, the European Union and the United States treat these products, and what developers should do to choose the right pathway from the start.

Executive summary

Microbiome medicine has moved from a scientific frontier to a regulated product class. The MHRA position paper is a clear signal that a treatment claim brings medicine grade obligations, and Canadian developers should plan on the same. The key points are below.

The UK position. The MHRA position paper of 18 August 2026 confirms that microbiome based medicinal products are regulated under the Human Medicines Regulations 2012, as biological medicinal products or, where they meet the criteria, as advanced therapy medicinal products.
Status. No microbiome based medicinal product currently holds a UK marketing authorisation. Faecal microbiota transplant can still be supplied through clinical trials, as an unlicensed special, or by extemporaneous preparation.
Canada is different. A product's pathway depends on its claim and composition: a treatment claim generally makes it a biologic drug, faecal microbiota therapy for recurrent C. difficile is handled under a Health Canada interim policy, and a probiotic sold for general health is usually a natural health product.
The US position. The FDA regulates live biotherapeutic products as biologics through its biologics centre, and two donor derived microbiota products are approved for recurrent C. difficile infection.
What to do. Classify early, because classification drives your manufacturing controls, your clinical evidence and the type of licence you can hold.

What are microbiome based medicinal products?

What it is. A microbiome based medicinal product is a medicine whose active ingredient is live microorganisms or microbial communities intended to prevent or treat disease. The class includes faecal microbiota products, single strain and defined strain live biotherapeutics, and engineered microbial therapies.

Why it matters. Because the active ingredient is alive and complex, characterisation, batch to batch consistency and safety are far harder to demonstrate than for a small molecule. That difficulty is exactly what regulators want to see controlled.

What to do. Define the product, its microbial composition and its intended claim before you choose a regulatory pathway. The claim, more than the biology, decides the framework.

It helps to separate two ideas that are often blurred. A probiotic supplement sold to support general wellbeing is a food or a natural health product. A microbiome based medicinal product makes a claim to prevent, treat or cure a disease, and is therefore a medicine. The same organism can sit on either side of that line. What moves it is the claim, the strain, and the level of risk.

What the MHRA now expects

What it is. The MHRA position is that microbiome based medicinal products fall within the existing UK medicines framework, so developers already have a defined route to a marketing authorisation.

Why it matters. Developers no longer face a regulatory vacuum. They can plan against the same standards of quality, safety and efficacy that apply to every UK medicine, which gives investors and partners more confidence.

What to do. Follow the scientific and regulatory steps the MHRA sets out, and decide early whether your product is a biological medicinal product or an advanced therapy medicinal product.

The position paper, published under the Human Medicines Regulations 2012, sets out the key considerations the MHRA expects developers to address:

Product characterisation. Identify and quantify the microbial composition, including strains and viable counts.
Manufacturing consistency. Control batch to batch variability with defined processes and release specifications.
Safety assessment. Address antimicrobial resistance risk, transmissible agents and, for donor derived products, donor screening.
Clinical evidence. Generate robust data on quality, safety and efficacy proportionate to the claim.
Classification. Confirm whether the product is a biological medicinal product or meets the criteria for an advanced therapy medicinal product.

Two practical points sit alongside the paper. No microbiome based medicinal product yet holds a UK marketing authorisation, so this is a route being opened rather than a settled market. And the existing supply routes for faecal microbiota transplant, through clinical trials, as an unlicensed special, or by extemporaneous preparation, are unchanged by the paper.

How Canada regulates microbiome products

What it is. In Canada there is no single microbiome medicine position paper. Instead the pathway depends on the claim and the composition, and the same organism can be a biologic drug, a natural health product, or a product supplied under the faecal microbiota therapy interim policy.

Why it matters. The framework you fall into decides your evidence burden, your manufacturing standard and your licence type. Choosing the wrong one, or drifting between them, creates real reclassification risk.

What to do. Map your claim to the right Canadian framework before you design the programme, and document the rationale so you can defend it.

Product or claim	Likely Canadian classification	Key requirements
Faecal microbiota therapy for recurrent C. difficile	Biologic drug under the FMT interim policy	Clinical trial application or access under the interim policy, donor screening, Good Manufacturing Practices
Defined strain live biotherapeutic with a disease treatment claim	Biologic drug, New Drug Submission	Clinical trial application, New Drug Submission, GMP, full characterisation
Probiotic with a general health claim	Natural health product	Product licence, site licence, NHP Good Manufacturing Practices, evidence to support the claim
Probiotic food, for example a yogurt with no drug claim	Food	Food safety and labelling rules

Health Canada's guidance treats faecal microbiota therapy as a biologic drug, while an interim policy applies a risk based interpretation of the clinical trial requirements for patients with recurrent C. difficile infection who are unresponsive to conventional therapies. A probiotic sold with a general health claim, by contrast, is usually a natural health product under the Natural Health Products Regulations, which require both a product licence and a site licence. The dividing line, again, is the claim and the risk. A disease treatment claim points firmly to the drug pathway.

The UK, Canada, the EU and the US compared

What it is. A side by side view of how four jurisdictions classify a microbiome medicine.

Why it matters. A developer running a cross border programme has to satisfy each framework, and the classifications do not map neatly onto one another.

What to do. Build a classification matrix for your product before you design the manufacturing and clinical programme, and align to the strictest applicable standard.

Jurisdiction	Framework	Classification of a microbiome medicine
United Kingdom, MHRA	Human Medicines Regulations 2012	Biological medicinal product or advanced therapy medicinal product
Canada, Health Canada	Food and Drug Regulations and NHP Regulations	Biologic drug, FMT interim policy, or natural health product by claim
European Union, EMA	EU pharmaceutical legislation	Biological medicinal product or advanced therapy medicinal product
United States, FDA	Public Health Service Act and FD&C Act	Live biotherapeutic product, regulated as a biologic

In the United States, the FDA regulates live biotherapeutic products as biologics through its biologics centre, and has approved two donor derived microbiota products for recurrent C. difficile infection. In the European Union, a microbiome medicine is a biological medicinal product or, where it meets the criteria, an advanced therapy medicinal product. The common thread across the UK, the EU and the US is that a product making a treatment claim is a medicine, held to medicine grade quality, safety and efficacy standards.

Where Canada differs, and why it matters

Canada does not have a single microbiome medicine position paper of the kind the MHRA has now published. Instead it distributes these products across the drug, natural health product and faecal microbiota therapy frameworks. For a developer, that split creates a classification risk that does not exist in the same way in the UK.

The risk is practical. A company that positions a live biotherapeutic as a natural health product to reach the market faster can face reclassification if its claims or its evidence look like those of a drug. The MHRA paper is a signal that regulators internationally expect medicine grade controls for anything that makes a treatment claim, and Canadian developers should assume Health Canada will take the same view. If you sell into more than one market, the safest course is to build to the strictest applicable standard and keep a documented classification rationale. Our article on how UK reliance affects Canadian manufacturers gives more context on how UK and Canadian decisions increasingly interact.

Microbiome product classification checklist

Use this checklist to decide, and defend, the pathway for a microbiome product. It is the basis of the downloadable worksheet at the end of this article.

Define the product's composition, including strains, communities and viable counts, and its intended claim before choosing a pathway.
Classify early: decide whether the claim makes the product a biologic drug, a natural health product, or an FMT interim policy product in Canada.
For a drug pathway, plan a clinical trial application and, where relevant, a New Drug Submission with Good Manufacturing Practices manufacturing.
Build product characterisation and potency assays that identify and quantify the microbial content.
Control batch to batch variability with defined manufacturing processes and release specifications.
Assess safety, including antimicrobial resistance genes, transmissible agents and donor screening for faecal products.
For a natural health product, hold a product licence and a site licence and match your evidence to the claim under the NHP Regulations.
Keep a written rationale for your classification so you can defend it if claims or evidence are challenged.
Map cross border differences across the UK, the EU, the US and Canada and align global programmes to the strictest applicable standard.
Reassess classification whenever the claim, the strain or the evidence changes.

Common mistakes

Assuming a microbiome product is automatically a supplement. The claim, not the marketing, sets the framework.
Positioning a live biotherapeutic as a natural health product to reach the market faster, then facing reclassification.
Underinvesting in characterisation and potency because the active ingredient is treated as just bacteria.
Ignoring antimicrobial resistance and transmissible agent risk in the safety package.
Treating UK, EU, US and Canadian requirements as interchangeable when they are not.
For faecal products, skipping donor screening or assuming the interim policy removes GMP expectations.

Frequently asked questions

What is a microbiome based medicinal product?

It is a medicine whose active ingredient is live microorganisms or microbial communities intended to prevent or treat disease. Examples include faecal microbiota products, single and defined strain live biotherapeutics, and engineered microbial therapies. It is distinct from a probiotic supplement, which does not make a disease treatment claim.

What did the MHRA decide in August 2026?

On 18 August 2026 the MHRA published a position paper confirming that microbiome based medicinal products fall within the existing UK medicines framework under the Human Medicines Regulations 2012. Depending on their characteristics they are regulated as biological medicinal products or as advanced therapy medicinal products, and no such product yet holds a UK marketing authorisation.

Are microbiome products drugs or supplements in Canada?

It depends on the claim and the composition. A product making a disease treatment claim is generally a biologic drug. A probiotic sold with a general health claim is usually a natural health product. Faecal microbiota therapy for recurrent C. difficile is handled as a biologic drug under a Health Canada interim policy.

How does Health Canada regulate faecal microbiota transplant?

Health Canada treats faecal microbiota therapy as a biologic drug. An interim policy applies a risk based interpretation of the clinical trial requirements for patients with recurrent C. difficile infection who are unresponsive to conventional therapies. Donor screening and Good Manufacturing Practices expectations still apply.

Is a probiotic a natural health product in Canada?

A probiotic sold with a general health claim, for example to support gut flora, is usually a natural health product under the Natural Health Products Regulations. It needs a product licence, a site licence, and evidence that supports the claim. A probiotic that claims to treat a disease would instead fall into the drug framework.

Do the UK, the EU and the US regulate microbiome medicines the same way?

They are similar in principle but not identical. The UK regulates them under the Human Medicines Regulations 2012, the EU under its pharmaceutical legislation, and the US as live biotherapeutic products through the FDA biologics centre. All three treat a product with a treatment claim as a medicine, but the exact classifications, submissions and terminology differ.

What should a Canadian developer do first?

Define the product and its intended claim, then classify it before designing the programme. That decision drives the manufacturing standard, the clinical evidence and the licence type. A gap assessment against the relevant Canadian framework, and against any export markets, is the practical first step.

How MFLRC can help

Microbiome products live on the border between medicines and natural health products, and the border is where companies get caught. MFLRC helps developers classify correctly and build the file that supports it. Our regulatory affairs, licensing and import and export team maps your claim to the right Canadian pathway, whether that is a biologic drug submission or a natural health product licence, and plans the submissions that follow.

For products entering the natural health product market, we prepare product and site licence applications and match evidence to the claim. For products on the drug or biologic pathway into the pharmaceutical market, our quality assurance and quality control services build the characterisation, potency and release controls a live product needs. If you export, our companion article on US requirements for Canadian NHP exporters is a useful next read.

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Conclusion

The MHRA has made the UK route for microbiome medicines clearer, and in doing so it has confirmed the direction of travel everywhere: a product that claims to treat disease is a medicine, held to medicine grade standards. Canada reaches the same destination by a different road, splitting these products across drug, natural health product and faecal microbiota therapy frameworks. For developers, the lesson is the same on both sides of the Atlantic. Classify early, characterise thoroughly, and keep a rationale you can defend.