It started, as many modern health trends do, quietly and online. Private sellers began offering something unusual: capsules, powders, and even enemas made from human stool, marketed as a natural way to fix digestion, restore “good bacteria,” and boost overall wellbeing. No prescription needed. No doctor involved. Just a message, a payment, and a package.
By September 2026, Spanish health authorities had seen enough.
A warning, not a rumor
On September 4, 2026, Spain’s National Transplant Organization (ONT) and the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) issued a joint public statement [1, 2]. Their message was unusually direct for a government health notice. These products, they said, were “neither safe nor effective” [1].
The warning named a specific pattern investigators had traced: individuals and at least one company, based in the Asturias region, selling stool-derived products such as capsules and freeze-dried preparations directly to consumers, completely outside any hospital or licensed medical channel [1].
What made the story land with such force wasn’t just the strangeness of it. It was the fact that a real, legitimate version of this treatment already exists, tightly regulated, medically supervised, and genuinely life-saving for the right patients. The danger wasn’t the science. It was the shortcut.
The real procedure behind the story
To understand what was being sold illegally, you first need to understand what a legitimate fecal microbiota transplant, or FMT, actually is.
FMT is a real medical procedure in which processed stool from a carefully screened, healthy donor is transferred into a patient, often through capsules or during a colonoscopy, to restore a healthy balance of gut bacteria [1, 6]. In Spain, this procedure exists under ONT oversight and only happens when a doctor determines it’s medically appropriate [1].
Its best-documented success story is treating recurring Clostridioides difficile infection, or C. diff, a brutal gut infection that can resist standard antibiotics entirely. In the United States alone, C. diff sickens roughly 450,000 people and kills close to 30,000 every year [5]. FMT has become a genuine lifeline for patients who’ve run out of other options, with at least 10,000 procedures performed annually for this reason, and hundreds of ongoing trials exploring other potential uses [6].
None of this happens casually. A legitimate FMT involves donor health screening, laboratory testing of the stool itself, controlled processing and storage, full traceability, and a medical team supervising the entire process [1]. Strip away those safeguards, and what’s left is not a shortcut to the same treatment. It’s something else entirely, and the story of what happens when those safeguards disappear had already played out years earlier, an ocean away.
When the safety net failed, even in a hospital setting
This part of the story isn’t Spanish, and it isn’t recent. It’s American, it’s documented by federal regulators, and it’s the clearest evidence of why this warning matters.
In June 2019, the U.S. Food and Drug Administration issued a safety alert that read like a cautionary tale made real. Two adults with weakened immune systems had received FMT prepared from the same donor’s stool. Both developed invasive bloodstream infections caused by a drug-resistant strain of E. coli. One of them died [3, 5].
The donor’s stool hadn’t been tested for that particular drug-resistant organism before the procedure [5]. It was only afterward, once both patients had fallen seriously ill, that investigators went back and tested a stored sample of the same donor material. It matched. The exact strain that had made both patients sick was sitting, undetected, in the stool that had been used to treat them [5].
The FDA’s response was swift. It halted a number of ongoing FMT clinical trials until researchers could prove they had stronger donor screening in place [6, 7].
Less than a year later, in March 2020, it happened again. This time, six patients developed infections from two different, dangerous strains of E. coli after receiving FMT. Four ended up hospitalized [4, 6]. Once again, the material traced back to a single donor whose stool had not been adequately screened for the pathogens involved [4].
Two separate safety alerts. Two different years. The same underlying failure: a shortcut in screening, however small, with consequences that reached all the way to a hospital bed.
Why the private, online version worries regulators even more
Here’s the part that should stop any reader from clicking “buy” on a product like this. The infections and death described above happened within supervised medical and research settings, where donors had still passed at least some level of initial screening [5, 6].
What Spanish authorities flagged in September 2026 involved no screening at all. No laboratory testing. No traceability. No medical supervision from start to finish [1]. If insufficient screening inside a controlled hospital protocol could still lead to serious infection and death, health officials argue, the risk of a product prepared by a private seller with no oversight whatsoever is far greater, and largely unknowable [1, 2].
Fecal matter, by its nature, can carry organisms capable of causing serious illness, and that risk climbs sharply when preparation, storage, or distribution happens under conditions nobody is checking [1, 2].
The pattern behind the story
This isn’t really a story about one company in Asturias, or even about Spain. It’s a story about what happens when a genuine, narrow medical treatment gets rebranded as a wellness product and sold to a much wider, much less informed audience.
Interest in gut health and the microbiome, the trillions of bacteria living in the human digestive system, has surged globally in recent years [2]. That curiosity is reasonable. Gut health really is connected to digestion, immunity, and general wellbeing. But that same curiosity has opened a door for sellers anywhere in the world to market something dangerous using the language of something legitimate.
The FDA’s warnings prove this isn’t a one-country problem. It’s a pattern that can, and has, repeated itself under different regulators, in different years, in different parts of the world [3, 4, 5, 6, 7].
What the story means for you, wherever you live
If there’s a single thread running through every version of this story, from Asturias to the FDA’s case files, it’s this: the danger isn’t fecal transplantation as a medical treatment. It’s fecal transplantation without medicine attached to it.
- Never buy or use a stool-derived product sold by a private individual or unverified company online
- Be skeptical of any online claim describing these products as “natural,” “safe,” or from “healthy donors,” since regulators say such claims lack scientific backing [1, 2]
- If you have a genuine digestive health concern, talk to a licensed doctor, who can refer you to a properly regulated FMT program if it’s appropriate for your case
- Report sellers of these products to your country’s health or consumer protection authority [1]
The story of the pills sold in secret isn’t over. But the documented facts, from a Spanish government warning to two separate FDA safety alerts and a patient’s death, all point to the same ending: when the safeguards disappear, so does the safety.
Disclaimer
This article is for general information only and is not a substitute for professional medical advice, diagnosis, or treatment. If you have questions about your gut health or are considering any microbiome-related treatment, please consult a qualified doctor. If you spot an error or have feedback on this article, please get in touch with us so we can correct it.
References
- [1] La Organización Nacional de Trasplantes alerta del riesgo de consumir cápsulas de heces, El Correo Gallego
- [2] Sanidad alerta del peligro de comprar preparados de heces humanas fuera de los canales médicos
- [3] Important Safety Alert Regarding Use of Fecal Microbiota for Transplantation and Risk of Serious Adverse Reactions Due to Transmission of Multi-Drug Resistant Organisms, FDA
- [4] Safety Alert Regarding Use of Fecal Microbiota for Transplantation and Risk of Serious Adverse Events, FDA
- [5] Patient dies after fecal transplant containing drug-resistant bacteria, NBC News
- [6] FDA warns about infections linked to fecal microbiota transplants, CIDRAP
- [7] FDA issues alert after fecal microbiota transplant death, CIDRAP
