Club-goers are always warned about being “roofied,” or drugged by Molly, an old drug — MDMA, or ecstasy — especially, after a string of overdoses last fall. Molly has been popping up more frequently not just at the clubs, but in pop culture, especially in songs, like Miley Cyrus’s “We Can’t Stop,” which references the drug. Despite its innocent-sounding name, Molly can be fatal even in moderate doses taken in hot temperatures, according to a recent study to be published in the Journal of Neuroscience.

“We know that high doses of MDMA can sharply increase body temperature to potentially lead to organ failure or even death,” said Dr. Nora D. Volkow, director at the National Institute on Drug Abuse (NIDA), in the news release. “However, this current study opens the possibility that even moderate doses could be deadly in certain conditions.” Researchers at the NIDA’s Intramural Research Program (IRP) believe while previous studies on moderate doses of Molly have been inconsistent when it comes to adverse effects, it can still be harmful if taken in moderation.

To investigate the effects of Molly on the body and brain in moderate doses, the team of researchers conducted a study using rats in a lab and administered low to moderate doses of the drug. Previously, these doses have been shown not to be fatal. The rats were monitored to observe whether any drug-induced changes occurred in the brain and body temperature environment. The body’s ability to cool itself through blood vessel dilation was also observed.

In high doses, Molly can interfere with the body’s ability to regulate temperature, according to the NIDA. In rare and unpredictable occasions, this can lead to a spike in body temperature — hyperthermia — and result in liver, kidney, or heart system failure, or even death. In the brain, Molly increases neurotransmitter activity in at least three neurotransmitters: serotonin, dopamine, and norepinephrine.

The findings revealed when the rats were alone and in a room-temperature environment, a moderate dose of Molly increased brain and body temperature and diminished the rats’ ability to eliminate excessive heat. However, when the researchers administered the same dose in rats that were either in a warmer environment or in the presence of another rat in the cage, brain temperature increased, leading to death in some rats. These fatal temperature increases were the result of the drug interfering with the body’s ability to eliminate heat.

“These results demonstrate that the use of MDMA in certain warm, social settings could be more dangerous than commonly believed,” said Dr. Eugene Kiyatkin, first author on the study and NIDA IRP scientist, in the news release. “Even with moderate doses, we saw drug-induced, fatal brain hyperthermia during conditions of social interaction and in warm environments.”

It has been well recognized that the drug greatly increases body temperature. Therefore, it is essential to control body temperature to prevent severe reactions to Molly. The possibility of hyperthermia can be avoided by providing the body with enough fluid, although drinking excessive water could lower salt concentration of body fluids and cause tissues to swell up in the brain, according to This may lead to death.

This study further warrants medical research on increasing the effectiveness of whole-body cooling by targeting blood vessel constriction in the skin, possibly counteracting MDMA-induced hyperthermia. The effects of Molly are of particular concern since most users of the drug are between the ages of 18 to 25, closely followed by those ages 12 or older.