Recently a patient of mine was hospitalized for liver failure due to alcohol. His history of liver disease was well documented, but he adamantly denied that anyone had warned him to avoid alcohol.

An initial confession of “a few drinks” turned into much more with a little probing by different medical providers. Despite his liver being in a significant amount of shock, he was stable and lucky enough to still have most liver function intact. After interviewing and examining him, I recapped why he had been hospitalized and explained that hospitalized for a few more days while we monitored his liver function.

As I was leaving the room, he asked me one final question: “Doc, do you think any of this has to do with the mold that was all over my old apartment building?”

Here was a patient with a damaged liver and little mystery about what had caused it, and yet here he was, with questions about… mold?

This was not the first—and certainly won’t be the last—patient to ask about mold. My patients have often wondered aloud whether mold is causing their breathing troubles, sinus congestion, overwhelming fatigue, and so on. Ultimately, I told this patient the same thing I told all the others: Mold exposure was not responsible for your health problems.

Mold worries are generally unfounded. There is no evidence that otherwise healthy individuals have any reason to fear falling ill from building mold, mold inhalation, or any other type of exposure to so-called toxic mold (PDF). Even when it comes to water-damaged buildings, any medically proven associations with health issues have come with long-term occupational exposures—not household exposures.

If you need more assurance, look no further than a study that examined residents of post-Katrina New Orleans: It didn’t find any increased risk of adverse respiratory effects from water-damaged buildings. This helps explain why the Centers for Disease Control and Prevention (CDC) doesn’t recommend routine mold testing in households, instead suggesting the U.S. Environmental Protection Agency’s (EPA) guide to mold control to ensure indoor air quality in high moisture environments.

That said, mold can cause health problems in certain populations—but typically, it only seriously affects patients who have underlying health conditions. Specifically, immunocompromised patients could be at risk of systemic fungal infections, and patients prone to allergic rhinitis or allergic asthma could have responses to inhaled mold.

There are skin and blood-testing methods available to determine whether patients truly have mold allergies or not. Additionally, anybody who has had long-term occupational exposure to mold could develop a rare disease known as hypersensitivity pneumonitis, which affects lung function. But beyond these medically established connections to mold exposure and medical illnesses, much of the rest is internet lore.

So, unless you’re in one of those rare categories, you don’t have anything to fear about exposure—and yet mold hysteria is fairly widespread. Why?

The answer is a depressing case study in internet-era medical misinformation, rumor-mongering, and irresponsible online doctoring. In short, some irresponsible people are drumming up fears about mold and then profiting off of those fears. These profits come at the expense of patients like mine who use these theories as scapegoats, failing to understand and tackle the real medical issues at hand.

On the surface, there certainly appears to be a wealth of online information about the supposedly harmful effects of mold exposure. A quick Google search of “mold” and “fatigue” will draw your attention to chronic fatigue syndrome (CFS).

Proponents of CFS justify the condition on the basis of one very flawed study that drew an association between mold and the syndrome, relying entirely on “urine mycotoxin” data—or the levels of fungal metabolites in urine. Not long the paper was published, the CDC issued a statement on the lack of clinical validity of urine mycotoxin tests, effectively invalidating its results.

When contacted for comment, Brewer said that he relies on the clinical picture and symptoms to diagnose CFS, based on the CDC’s 1994 case definition. He still offers urine mycotoxin testing to his patients, despite the CDC’s own website clearly stating that there is no “lab test or biomarker” for CFS and no single identifiable cause.

The mold-CFS internet monster is nothing compared to the “Surviving Mold” empire created by Dr. Ritchie Shoemaker. Shoemaker’s website discusses mold-induced chronic inflammatory response syndrome (CIRS) ad nauseum. This disease encompasses a gamut of vague symptomatology, defined as “an acute and chronic, systemic inflammatory response syndrome” in response to mold, bacteria, and other “pro-inflammatory” exposures. The scientific evidence to back up CIRS is severely lacking, and if you search for more details on specific clinical descriptors, you will end up empty-handed.

Perhaps inevitably, Shoemaker offers to train (for a fee) other physicians with his “Shoemaker Protocol,” a program to help them detect and treat CIRS. Online memberships are offered for all website visitors, ranging in price from $19.50 per month to $175 for a 12-month subscription. The memberships offer screening tools, email consultations with Shoemaker, and other “Surviving Mold” materials.

Despite the fact that Shoemaker has been out of clinical practice since 2013 and has come under fire by both his state medical board and the Food and Drug Administration (FDA) for unregulated online portal and practice methods, the website is still thriving and propagating myths that spread to other “alternative health” websites.

When asked for comment, Shoemaker told The Daily Beast “you have your facts wrong,” and declined to reply to further emails.

If any myth is more pervasive than that of toxic mold and systemic illness, it is the earlier mentioned water-damaged buildings and “mycotoxicosis” legend. Proponents of mycotoxicosis suggest that mold in such buildings can trigger inflammatory processes that lead to immunologic changes and a gamut of symptoms—ranging from neurological complaints to pulmonary issues. The study of post-Katrina New Orleans residents should have debunked all of this, but there still is a wealth of false information online about water-damaged buildings and the illnesses they allegedly cause.

Here, one of the biggest figures is a Dr. William Rea, who came under fire from the Texas medical board for multiple complaints, including using “pseudoscientific test methods,” offering inaccurate diagnoses, providing inappropriate treatments, practicing in an area beyond his expertise, and failing to fully disclose his practice approach with his patients. In the wake of a settlement he reached with the board in Texas, Rea was ordered to modify his patient consent forms to note that his therapies have not been therapeutically proven and are not FDA-approved.

But remarkably, Rea’s Environmental Health Center is still open in Dallas, billing itself as a “complete testing and treatment facility for chemically-sensitive adults and children.” Rea is actually only board certified in cardiovascular and general surgery. Requests for comment from Rea went unanswered.

The bottom line: Don’t believe the hype. There’s a very real reason why doctors caution patients about information available on the internet. People who might be susceptible to mold-related health effects are usually only vulnerable because of underlying health conditions, so this is a case of the chicken before the egg—or in this case, the patient before the mold.