Marijuana has a reputation for being a safe drug, but some researchers say there is mounting evidence that the drug is associated with adverse heart complications. In two new case studies, two young men in Germany—ages 23 and 28—with no drugs other than THC in their systems and no known health issues (though the 28-year-old had used other drugs up until a few years ago), both died due to complications from abnormal heart rhythms, or arrhythmias.

"After exclusion of other causes of death, we assume that the young men died from cardiovascular complications evoked by smoking cannabis," the researchers conclude. They added that the two men may have also been predisposed to cardiovascular risks.

Though the researchers tell LiveScience there have been some "quite unpleasant reactions from individuals" following their report, and while some researchers say there isn't a strong enough link to implicate marijuana, there is mounting evidence that there are "marijuana-associated adverse cardiovascular effects, especially in young people," an author of a similar study said in an American Heart Association statement.

Either way, one toxicologist says people should proceed with caution: "Some people who are predisposed to cardiac events may be particularly vulnerable to potential harmful effects of marijuana use, and the new report shows this." (Berkeley, meanwhile, recently voted to give free medical marijuana to the poor.)

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