The Food and Drug Administration warned an e-cigarette manufacturer Thursday to stop putting the key ingredients of an erectile dysfunction drug and an anti-obesity drug into vaping liquid.

The warning letter is another part of a broad crackdown on e-cigarette makers and retailers meant to curb the growing use of the product among minors. But this is the first warning letter sent to a company for adding prescription drugs into an e-cigarette liquid, the agency said.

The letter was sent to HelloCig Electronic Technology Co. for selling two e-cigarette liquids, one containing the active ingredients of erectile dysfunction drug Cialis and the other the ingredients for anti-obesity drug Acomplia.

“These FDA-approved prescription drugs are not approved for inclusion in e-liquid products sold over the counter and are therefore being sold illegally,” the FDA said in a statement on the warning letter to HelloCig.

The FDA also warned the company for marketing the products in a misleading way. For instance, the liquid containing Cialis ingredients is marketed with an image of a Cialis bottle.

“Use of these trade names and images of the drug products next to the e-liquid products on HelloCig’s website suggests that the products are intended to treat the same conditions as the drug itself,” the FDA said.

It also said that HelloCig was illegally marketing some products as FDA-approved when they weren’t.

The agency requires e-cigarette manufacturers to apply for agency approval of a product that is on the market after a “grandfather” date of Feb. 15, 2007.

The FDA told the Washington Examiner it could neither confirm nor deny that HelloCig filed any application for approval.

A request for comment from HelloCig on the application and the warning letter was not returned.

The agency gave the manufacturer 15 days to state how it will address the violations. If the company doesn’t respond, then the FDA could ask the Justice Department to seize the products from shelves.

FDA has gone after e-cigarette makers in recent months but mainly for marketing or illegal sales to minors.

Last month, FDA Commissioner Scott Gottlieb floated banning e-cigarettes after the agency gave out 1,300 warning letters and fines to retailers for e-cigarette sales to minors.

The FDA also raided the headquarters of e-cigarette giant Juul Labs, whose products are popular among teens and adolescents because they resemble a USB drive and are unrecognizable as e-cigarettes to teachers and parents.

[Opinion: The FDA is (unintentionally) going to make people smoke more]