October 15, 2015 2:53 PM EDT

The U.S. Food and Drug Administration warned consumers earlier this month not to buy the “all natural” sexual enhancement supplements often called “herbal Viagra,” which was among the drugs former NBA star Lamar Odom reportedly took before he was found unconscious in a Nevada brothel this week.

“Products falsely marketed as ‘dietary supplements’ or ‘foods’ that promise to enhance your sexual performance or increase sexual stimulation might contain hidden drug ingredients or other undisclosed ingredients — and can endanger your health,” the agency said in an Oct. 1 consumer alert.

Sexual enhancement supplements are available over the counter and are thought to be cheaper than the FDA-approved drug Viagra, which treats erectile dysfunction. But since the supplements are not approved by the FDA, the agency has warned about their use in the past. Odom has been in a hospital since he was found unresponsive on Tuesday.

“We’re finding an alarming number of these products sold online and in retail stores,” Gary Coody, the FDA’s national health fraud coordinator, said in a statement accompanying the consumer alert. “They’re often sold in single-serving sizes in gas stations or vending machines. We’ve seen pills, coffees, chewing gum and dissolvable oral strips that contain hidden drug ingredients or untested chemicals.”

Lab tests conducted by the FDA had shown that close to 300 supplements actually contain undisclosed drug ingredients. “These can include the same active ingredients found in prescription drugs that are FDA-approved for the treatment of erectile dysfunction (ED), such as Viagra, Cialis and Levitra,” the FDA said.

Since the supplements do not undergo safety testing, they can contain high doses of ingredients, or drug combinations, that could result in adverse health consequences. Buyers can be misled into thinking the products are safe by labels that read “all-natural” and “herbal,” but some of the ingredients may not be listed on labels. The FDA has released separate, specific warnings about such products, such as Plant Vigra and Herb Viagra. Both were found to contain sildenafil, which is an active ingredient in the drug Viagra. These supplements could interact poorly if a man is also taking other medications.

The FDA says some of the supplements contain chemicals that have not undergone safety testing in the United States. Consumers should also be wary of products that promise results in as little as 30 minutes, are marketed as alternatives to prescription drugs, have labels written mainly in a foreign language, and have directions and warnings that are similar to FDA-approved products.

Contact us at letters@time.com.

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