TORONTO, Canada — The United States Food and Drug Administration has issued a warning letter to a company that appears to sell products containing human fecal matter without approval from the agency.

In March, the FDA wrote to Human Microbes, a company advertising itself as “the world’s largest, highest quality stool donor bank” for fecal microbiota therapy transplants, after reviewing its website a month prior.

According to Health Canada, fecal microbiota therapy is the transfer of bacteria from the feces of a healthy person to the gut of a patient to re-establish a healthy microbiome, executed through enema, colonoscopy, or other means.

This type of therapy should only be used in the context of an authorized clinical trial, or to treat patients with recurrent Clostridium difficile, also known as C. difficile, a bacteria that causes diarrhea and intestinal conditions, like colon inflammation, the agency said.

Per Human Microbes’ website, the therapy yields “promising results in clinical trials” to treat other conditions, such as irritable bowel syndrome, Parkinson’s disease, multiple sclerosis and mental health disorders like depression and anxiety, among others.

In the FDA’s letter, the agency says that to “lawfully market” these biological products, a valid biologics license application is needed. An FDA-approved application must be in effect to introduce and deliver them. Additionally, an investigational new drug application must be in place for products to be distributed to people in clinical trials while in the development stage.

According to the FDA, Human Microbes does not have any of the required applications and consequently are “both unapproved new drugs and unlicensed biological products.”

The administration also notes that, per its guidance issued in November 2022, the treatment for other conditions outside of C. difficile has more limited data, and the study of this treatment for other uses is not included in the FDA’s enforcement discretion policy.

“Although your website recommends that patients ‘discuss their plans with their doctor,’ it offers your products directly to patients, including for self-administration,” the letter reads. “Therefore, there is no assurance that a licensed health care provider treating each of these patients is directing the screening and testing of the stool donor and stool for the patient, as described in the November 2022 guidance.”

The letter also says these particular products raise “potential significant safety concerns,” due to insufficient screening.

The FDA advised Human Microbes to review its website and materials to ensure it is compliant under the Federal Food, Drug, and Cosmetic and Public Health Service acts, asking for a response on what the company’s next steps will be to correct any violations or provide reasoning on why the products are not in violation.

Rebyota and Vowst are currently both listed as FDA-approved fecal microbiota products.

Human Microbes’ founder Michael Harrop said they intended to run the products as a clinical trial, “but all I could find were companies charging $1,500 to tell you whether or not it was possible.”

“I also contacted the FDA about getting approved for an IND (investigational new drug) application and never heard back. So I continued as is,” Harrop’s post reads. He agrees Human Microbes should be regulated, but as a “source of stool donors” rather than a drug developer.

“I’m searching for people healthy enough to be stool donors. Researchers, doctors, clinical trials, etc., can then purchase stool from our donors. I’m not sure what the exact requirements are, but it is widely stated that IND requirements are extremely onerous,” Harrop’s post reads.

Harrop told CTV News that a meeting with the FDA is scheduled for next month, “after which I plan to post a new blog about major changes, regardless of what the FDA decides. But the blog will also cover what happens with the FDA.”

While Health Canada didn’t comment specifically on Human Microbes, the agency said only authorized products can be advertised and sold in the country.

“Selling unauthorized health products or making false or misleading claims to prevent, treat or cure illnesses is illegal in Canada.”