It impairs the activity of immune cells in your lungs, which work to prevent respiratory infections, by impairing their ability to kill bacteria and fungus, Dr. Tashkin said.
There is “absolutely no comparison” between the safety of marijuana and tobacco smoke, Dr. Tashkin added, noting that the latter is the top cause of preventable deaths in the United States. No one has ever overdosed on marijuana, and no major studies have found a significant increase in lung cancer risk from the drug.
Tetrahydrocannabinol, or THC, the active psychedelic ingredient in cannabis, has known anti-tumoral effects, Donald P. Tashkin, M.D., a pulmonologist at UCLA who has studied marijuana for more than 30 years, told weather.com. “It’s been shown by a large number of investigators to [reduce] growth of brain, lung, breast, prostate and thyroid cancer cells in animal models,” he said.
There are known carcinogens in marijuana smoke the same that’s in tobacco smoke. We also know that there are pre-cancerous changes in the [airways] of heavy marijuana users who don’t smoke tobacco.”