This is an updated version of a story that originally ran in 2017.
Friday is April 20, better known to many as 4/20, or “Weed Day.” People around the world are celebrating the unofficial marijuana holiday by gathering for rallies, smoke-outs, policy discussions and thousands of other weed-centric events.
It’s a day of blissful hypocrisy for millions of cannabis users in the U.S., who by and large are still expected to be somewhat covert about their fondness for the plant. The federal government maintains that marijuana is a dangerous illegal drug, with no accepted medicinal value and a high potential for abuse. Despite repeated calls for the reclassification of cannabis, it remains on the Drug Enforcement Administration’s list of Schedule I substances ― which also includes heroin, mescaline, LSD and a broad category of synthetic stimulants often referred to as “bath salts.”
The government’s message is clear: Marijuana and the psychoactive compound within it ― tetrahydrocannabinol, or THC ― poses a severe hazard to your health. To get a better sense of just how dangerous these substances are, The Huffington Post set out to compile a list of every person who has ever died solely as the result of a marijuana overdose.
Here’s what we found:
There are no recorded instances of anyone dying from a fatal dose of marijuana alone.
Nothing has changed since the last time HuffPost highlighted this fact in 2013. And because the list was once again relatively easy to compile, we had time to find this GIF of a dog with the munchies. He did not overdose on marijuana ― though dogs can, so keep that in mind. He is also a good boy.
Fatally overdosing on marijuana in its most commonly ingested forms is seemingly impossible. In 1988, a DEA judge argued in favor of rescheduling marijuana in part because of its low harm profile. In his ruling, he wrote that a user would have to ingest somewhere between 20,000 to 40,000 times the amount of THC contained in a single joint to approach lethal toxicity.
“A smoker would theoretically have to consume nearly 1,500 pounds of marijuana within about fifteen minutes to induce a lethal response,” wrote Judge Francis Young.
Study results vary, but some suggest a lethal dose of marijuana may be even higher. Extrapolating from cannabis toxicity research on monkeys, a human would have to orally ingest more than 2.9 grams of THC per kilogram of body mass to be at risk of poisoning. At 88kg, the average American man would have to down more than an 9 ounces of 100 percent THC extract. That’s almost certainly not possible, but if it were, it might involve taking this “Dragon Ball” to the face.
“That’s far more than most people will consume throughout their entire lifetime,” said Jahan Marcu, chief science officer at Americans for Safe Access, an organization that advocates for cannabis as medicine.
The lack of death by marijuana poisoning doesn’t mean people haven’t been trying. Humans have been getting high since prehistoric times and for millennia, cannabis ― both in its flower and concentrated hashish forms ― has been one of our favorite intoxicants. People aren’t particularly prudent in their efforts to chemically alter their consciousness, so if it were possible to use a fatal dose of marijuana, it seems like someone would have done it. In fact, if some poor soul had managed to blaze up the close to a ton of herb necessary to achieve this morbid feat, you can be damn sure it would be the stuff of legend.
“People have tried to ingest as many plant cannabinoids as possible and there is no fatal overdose that has ever been documented in human beings,” Marcu said.
Opponents of marijuana might argue that just because it hasn’t happened before doesn’t mean it can’t happen in the future. They often point to growing concentrations of THC in modern pot plants as a cause for concern about increased harm. This ignores some important historical context, said Marcu.
“When you put those potency values on the scale of products that have been available and distributed and traded over millennia, they’re actually probably less potent than what someone would have gotten from a Moroccan hash trader a thousand years ago,” he said.
Although the era of “Reefer Madness” is not completely over ― just listen to some of the officials in the Trump administration ― it has proven increasingly difficult for the federal government to keep people scared about the supposed dangers of marijuana.
With tens of millions of Americans regularly reporting having used weed in the past year, it is the most commonly used illicit substance in the United States. Eight states and Washington, D.C., have now approved marijuana for recreational use, though sales remain banned in the nation’s capital. A total of 29 states have legalized marijuana for medical purposes.
In 2006, a study in American Scientist compared the relative toxicity of marijuana to other commonly used substances, including some legal ones. It found that just 10 times the effective dose of alcohol and five times the effective dose of heroin could be enough to cause death in humans. Marijuana ranked among the least toxic drugs.
None of this is to say that using marijuana recreationally is as safe or as healthy as it would be to abstain completely. Although the science on even the most basic physiological effects of marijuana use remains incomplete and highly politicized, in rare cases it has been associated with disturbing adverse reactions. Studies have found that THC can exacerbate certain preexisting mental health conditions in some people, especially among younger users. Cannabis use has also been cited, albeit controversially, as a contributing factor in a handful of deaths of people with underlying cardiovascular conditions.
But scientists say the nature of these links is often inconclusive, inconsistent and highly dependent on the condition of the person using marijuana.
“There have been some associations seen with heavy cannabis use and development of possible psychotic behaviors, for example, but we don’t know if it’s a causal pattern,” said Sunil Kumar Aggarwal, a clinical instructor at the University of Washington’s school of medicine. “If it is, I can’t prove it.”
In states that have legalized cannabis, emergency rooms have reported an uptick in instances of cannabinoid hyperemesis syndrome, a mysterious illness that causes severe abdominal pain and vomiting. But these symptoms are not life-threatening and can be treated by stopping marijuana use, Aggarwal said.
Although a heavy dose of weed may not kill you, it’s certainly been known to make people feel uncomfortably high, leading to dysphoria, agitation, anxiety or panic. Those effects can seem like they last an eternity, but they’re reversible and tend to get better over a window of a few hours.
Sometimes, using marijuana in extreme excess can lead to poisoning or nonfatal overdose. But even then, the long-term damage pales in comparison to many other drugs. Aggarwal points out that taking too much of a common pain reliever like ibuprofen or acetaminophen can do serious harm to the liver, kidneys or stomach.
“We don’t see those kind of end organ damages with cannabinoids, especially natural-form extracts and that kind of thing,” he said.
It’s also important to remember that the conversation around marijuana use extends far beyond those who use it recreationally while celebrating on 4/20. Many people already rely on cannabis as a medicine. Even if the federal government won’t openly acknowledge its therapeutic effects, marijuana-based prescription pharmaceuticals like Marinol and cannabidiol treatments for epilepsy are proof that the plant’s benefits and harms are not as clear-cut as the DEA makes them out to be.
“These marijuana-derived products and purified forms of cannabis that have THC in them have been around for decades, and they’ve been prescribed to treat neurological disorders, not to cause them,” Marcu said. “If it was so bad for our nervous system and our brain, why is the first person we give it to someone who has multiple sclerosis, or HIV-AIDS, or neuropathy, or cancer, or a child with a disease?”
Clarification: This story has been updated to replace a reference to a study on the toxicity of marijuana for humans with another citation, as the origin of the initial citation was unclear. It also has been updated to amend a quote that misstated the effects of overdoses of acetaminophen and ibuprofen.