The U.S. Food and Drug Administration is giving the maker of Purell products a stern warning: Stop making unproven claims that over-the-counter hand sanitizers help eliminate Ebola, MRSA or the flu.

In a "warning letter" to Purell's parent, Gojo Industries, the agency called out the company for making numerous marketing claims that potentially position its sanitizing products as a pharmaceutical drug rather than an over-the-counter topical antiseptic.

The letter from the agency's director of compliance cited numerous examples of what the FDA says are unproven claims for Purell products made on gojo.com, purell.com, and social media accounts for the brand.

The products at issue include Purell advanced hand sanitizer gentle & free foam, Purell advanced hand sanitizer gel and Purell advanced hand sanitizer gentle & free foam ES6 starter kit. These products, the FDA noted, are commonly sold for use in places like athletic facilities, schools, and offices.

Among them: Purell "Kills more than 99.99% of most common germs that may cause illness in a healthcare setting, including MRSA & VRE"; and "Purell Advanced Gel, Foam, and Ultra-Nourishing Foam Hand Sanitizer products demonstrated effectiveness against a drug resistant clinical strain of Candida auris in lab testing."

Gojo could not immediately be reached for comment.

Within the "Frequently Asked Questions" section on gojo.com, the agency noted the company says that "Purell Healthcare Advanced Hand Sanitizers, which are formulated with ethyl alcohol, may be effective against viruses such as the Ebola virus, norovirus, and influenza."

That, too, is an unproven claim, the FDA says. The agency said it was not aware of any hand sanitizers that have been tested against Ebola viruses, including Purell's products.

Federal regulators also took issue with the company saying that Purell products are proven to "reduce student absenteeism by up to 51%."

The FDA doesn't allow hand sanitizer brands to make claims about efficacy against contracting viruses, such as any stating that Purell hand sanitizers are effective against the flu. However, the agency noted that the Centers for Disease Control and Prevention recommends using alcohol-based hand sanitizer for flu prevention. Purell is made of ethyl alcohol.

The agency said Gojo Industries' marketing message about Purell appeared to give the impression that Purell products are drugs, "because they are intended for the diagnosis, cure, mitigation, treatment, or prevention of disease."

That gives Gojo Industries two options: It can market Purell as a drug, and file a new application to get approval for the Purell products to be classified as such. Or it can stop making those marketing claims altogether.

Until then, the FDA considers the hand sanitizers to be unapproved drug products. The agency said it expects Gojo Industries to investigate and correct the violations or face legal action and potential seizure of Purell products.

Other personal care brands in the past have also been in the crosshairs of regulators over unproven product claims. The FDA, for example, has taken Johnson & Johnson to task for making claims that its mouthwash product Listerine was effective in removing plaque or preventing gum disease.

The warning to Gojo Industries comes at a time when China's coronavirus outbreak is causing fear worldwide about an impending pandemic.