Marijuana Side Effects on the Body: Guide

Quick answer

Cannabis changes heart rate, blood pressure, memory, coordination, and mood within minutes. Smoked effects peak in 10 to 30 minutes and fade in 1 to 3 hours. Edible effects start in 30 to 90 minutes and last 4 to 8 hours. Some effects last longer than the high.

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Short-term effects on the body

Heart and circulation

Smoked cannabis raises heart rate by 20 to 50 beats per minute. Blood pressure can fall when a person stands, which causes dizziness. One study found heart attack risk rose about 4.8 times in the first hour after smoking. Risk is higher in people who already have heart disease.

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Eyes, mouth, and appetite

Red eyes come from widened blood vessels in the conjunctiva. Dry mouth comes from less saliva. Appetite often rises.

marijuana side effects on body

Brain, memory, and movement

THC binds CB1 receptors in the brain. Short-term memory, attention, and reaction time drop. Balance and hand control get worse. Driving within 3 hours of use raises crash risk. Anxiety and paranoia can follow high-THC products. Edible doses above 10 mg THC raise the chance of panic and vomiting.

Long-term effects

Lungs

Cannabis smoke carries tar and irritants. Daily smoking links to chronic cough, phlegm, and bronchitis. The smoke holds many of the same cancer-causing chemicals as tobacco smoke. Lung cancer risk from cannabis alone is not settled.

Teen brain

Use before age 18 links to memory and attention problems that persist after stopping. The brain keeps developing to about age 25.

Mental health

High-THC products link to psychosis in people with a family history of schizophrenia. Evidence that cannabis causes schizophrenia in people with no risk factors is mixed.

Pregnancy

THC crosses the placenta. Use during pregnancy links to lower birth weight.

Dependence and withdrawal

About 3 in 10 people who use cannabis develop cannabis use disorder. About 1 in 6 who start before age 18 do. Withdrawal brings irritability, sleep problems, and lower appetite. Symptoms peak in the first week and ease over 2 to 3 weeks.

Cannabinoid hyperemesis syndrome

Long-term daily users can get repeated vomiting, belly pain, and nausea. Hot showers or baths ease symptoms for some people. Stopping cannabis ends the cycle.

Get medical help for

• Chest pain or pressure
• Fainting
• A fast heartbeat that does not slow
• Repeated vomiting or signs of dehydration
• Severe confusion
• Hearing voices or paranoia that does not pass
• Thoughts of self-harm