“Marijuana is basically harmless since it's natural.”
Strong confidence because major evidence reviews and current public-health guidance document cannabis-related impairment, cannabis use disorder, pregnancy concerns and mental-health risks. The size of each risk varies with age, frequency, THC concentration, route and individual vulnerability.
Being natural does not make cannabis harmless. It can impair driving, lead to cannabis use disorder, expose the lungs to smoke and increase mental-health risk in some people.
Cannabis has evidence-supported medical uses for some conditions, but a possible medical benefit does not make every product, dose or pattern of recreational use safe.
Safety note: Do not drive while impaired. Avoid cannabis during pregnancy, keep edibles away from children and use extra caution with high-THC products or a personal or family history of psychosis.
Talk to a healthcare professional if: Discuss use with a clinician if you are pregnant, have worsening anxiety or unusual thoughts, cannot cut back, use cannabis with sedating medicines or are considering it for a medical condition.
Cannabis is neither harmless nor equally risky in every situation. Younger age, frequent use, higher THC and inhaled smoke can increase risk.
If you use cannabis, avoid driving, pregnancy and child access, and reduce frequency or potency if use is affecting sleep, mood, memory or daily life.