Here's how much marijuana it would take to kill you

Nearly half of Americans say they have tried marijuana at least once in their life.

With more people lighting up than ever (and nine states voting on the legalization of marijuana on Election Day), it's important to remember how many fatally overdose on the drug.

Zip. Zero. That's according to the National Institute on Drug Abuse, which collects data on a range of other substances, both legal and illicit, and the Drug Enforcement Administration.

For comparison, opioids, which include prescription pain relievers and heroin, killed more than 28,000 Americans in 2014. Nearly 88,000 people die from alcohol-related causes every year, which makes alcohol the fourth leading preventable cause of the death in the US.

It's pretty impossible to ingest a lethal dose of marijuana.

David Schmader, author of "Weed: The User's Guide," spoke with experts and crunched the numbers on how much bud it would take to kill someone.

"Even aspirin can kill you if you take too much, but a fatal dose of marijuana would require ingestion of fifteen hundred pounds in fifteen minutes - a physical impossibility for any human, even Snoop Dogg," Schmader writes in his book.

This handy diagram from "Weed: The User's Guide" might help:

One reason for this impossibility is the way the brain works. When a user ingests marijuana, chemicals in the plant ride the nervous system to the brain and latch onto molecules called cannabinoid receptors. Those little holding cells influence pleasure, memory, coordination, and cognition, among other functions, which is why getting high affects thinking and behavior.

Cannabinoid receptors are not found in the brainstem areas that control breathing. Thus, "lethal overdoses from cannabis and cannabinoids do not occur," The National Cancer Institute explains.

Marijuana isn't harmless, however. The psychoactive ingredient that gets users high, tetrahydrocannabinol, or THC, is a powerful intoxicant. Having physical abilities and judgments impaired can lead users to put themselves in unsafe situations.

REUTERS/Lucy Nicholson

An employee holds out a jar of dried cannabis buds a patient at the La Brea Collective medical marijuana dispensary in Los Angeles, California.

And while there are no recorded cases of deaths from marijuana overdose, one bong rip too many can make users feel incredibly uncomfortable. Their heart starts to race, hands tremble, and anxiety strikes. There are things they can do to mitigate a "What I have done?" high.

In his book, Schmader recommends users tell themselves that they're in no real danger.

Drink some water to stay hydrated and eat a snack - preferably one that is ready-to-eat and does not require operating a stove - to boost your blood sugar. Call up a trusted friend, Schmader says, or Google search "Maureen Dowd Colorado" to feel less alone.