A Dutch institute working on addiction and mental health has issued a “red warning” about ecstasy and “joy” pills shaped like Donald Trump, the U.S. president, which are available on the market and can be deadly.

The Trimbos institute, based in Utrecht, the Netherlands, announced that in August of this year, several samples of these pills were delivered to drug testing centers and it was determined that they contained a “very high” amount of a chemical called PMMA.

PMMA, or paramethoxy-methamphetamine, is a substance similar to MDMA and is considered the active ingredient in ecstasy tablets.

In its warning, the institute said that “under no circumstances use these pills” and warned that taking them can cause “overheating of the body with potentially fatal consequences.”

The Trimbos institute published images of these pills, showing a Trump face on one side and the words “Trump” and “NL” (an abbreviation for the Netherlands) engraved on the other.