The Impact on the Body Chronic marijuana smokers are prey to chest colds, bronchitis, emphysema, and bronchial asthma. Persistent use will damage lungs and airways and raise the risk of cancer. There is just as much exposure to cancer-causing chemicals from smoking one marijuana joint as smoking five tobacco cigarettes. And there is evidence that marijuana may limit the ability of the immune system to fight infection and disease. Marijuana also affects hormones.
Regular use can delay the onset of puberty in young men and reduce sperm production.
For women, regular use may disrupt normal monthly menstrual cycles and inhibit ovulation. When pregnant women use marijuana, they run the risk of having smaller babies with lower birth weights, who are more likely than other babies to develop health problems. Some studies have also found indications of developmental delays in children exposed to marijuana before birth. Anecdotal assertions of beneficial effects have yet to be confirmed by controlled scientific research. Although dangers exist for marijuana users of all ages, risk is greatest for the young.