Skip to main content
Family of four plays at the beach with coastline in background

Marijuana may be legal, but is it safe?

January 23, 2018 | UCI Health
marijuana in a jar

Now that marijuana is legal in California for recreational use, it’s important to understand that today’s cannabis is not your great-grandmother’s weed.

If you haven’t smoked pot recently, you need to proceed with caution, says UCI Health substance abuse expert Bharath Chakrvarthy, MD, MPH.

“Marijuana is a lot more concentrated today,” warns Chakravarthy, associate professor of clinical emergency medicine and public health. “If you are using marijuana, make sure you do it responsibly.”

Much research still needs to be done on the effects of marijuana, which is a mind-altering drug. As with alcohol and other controlled substances, people also need to be aware that marijuana affects individuals differently.

Precautions you can take

In the meantime, Chakravarthy advises people who decide to experiment to take the following precautions:

  • Do your research first.
  • Read up on today’s products and methods for safely ingesting them.
  • Buy only from sources you are familiar with. Buds, edibles or concentrates purchased on the street could be laced with other substances, including methamphetamines or other dangerous compounds.
  • Keep it away from kids. Marijuana can be extremely toxic to young bodies. Last year, 60,000 children ended up in emergency rooms after getting into their parents’ medicine cabinets. Store marijuana just as you would Vicodin or sleeping pills. Know, too, that teens will find it, so be especially careful, even if you have to stash it in a locked safe or box.
  • Keep pot away from pets. If animals ingest marijuana intended for human consumption, they can become extremely sick.
  • Never drive under the influence. Marijuana affects decision making and slows reaction times. A study conducted by Chakravarthy found that 30 percent to 35 percent of people who are taken to an emergency department after a car crash had taken illicit substances, including marijuana. Moreover, they were unaware that they shouldn’t drive under the influence of prescription drugs or marijuana.

“People are going to experiment,” Chakravarthy says. “But we just don’t know enough yet to say what is the safest way to use marijuana.”

Limited data on marijuana

Until data is available to give a more complete understanding of cannabis’ effects, here’s what we do know:


There’s no evidence that smoking marijuana causes cancer like cigarettes do, but chronic users face some of the same effects as smokers by inhaling the same tars and irritants. “Everything in life and in medicine is dose-dependent,” Chakravarthy says. “Frequency of use, concentration of use, and individual characteristics all come into play.”

There is also no research on the effects of inhaling second-hand marijuana smoke.


Vaporizers heat marijuana to release its active ingredients without burning, which can mean fewer toxins and less lung irritation. “There are some pretty good studies that suggest that vaping may be safer than smoking,” Chakravarthy says, “but the verdict is still out.”

Even so, one should be wary of the chemicals used to produce the vapor. A recent federal study found that some aerosol mists from e-cigarettes contain a toxic brew of carcinogens.

Dabbing of cannabis wax

Dabbing involves inhaling fumes from a super-concentrated piece of marijuana in wax form that is heated on a hot surface. Butane — a carcinogen in high concentrations — is used in making the potent wax. Is there an increased risk of cancer or lung disease? “We don’t know the answer,” says Chakravarthy. “But there is some concern.”


Marijuana-laced edibles are increasingly popular, especially since smoking isn’t involved. Since the business is unregulated, it’s hard to know exactly what’s in those cookies, candies and drinks. The amount of THC — tetrahydrocannabinol, the active ingredient in marijuana — in these products is definitely greater than in your college-era brownies. Plus, since it takes up to 30 minutes to begin to feel the effects, there’s a real danger of ingesting more than you need or want.

Applying CBD oils and creams

CBD — or cannabidiol, one of the many chemical compounds in marijuana — doesn’t produce a high. But there is some medical promise for using CBD oils and creams for conditions including depression, addiction, Parkinson’s disease and even epilepsy in children.

“Researchers at UCI and other places are investigating CBDs for these and other neurological and behavioral diagnoses,” Chakravarthy says. “However, it worries me as a physician if people elect to use them on their own.”

Related stories

  • Want monthly health tips emailed to you? Sign up here!

    * indicates required