Medical marijuana

April 2005     View PDF     En español

Lung complications

Research comparing the effects of tobacco and marijuana smoking on the lungs shows that marijuana smoke can be harmful. Smoking marijuana increases the risks of lung complications, may worsen asthma and may increase the risk of lung cancer over and above smoking tobacco.

Another possible harmful effect of smoking marijuana is that it may cause lung infections. In particular, a fungus sometimes found in marijuana called aspergillus is thought to be the cause of possible infections. This infection has sometimes been seen in people with advanced HIV disease.

Some recommend putting marijuana in the microwave for ten seconds to kill any fungus that might be growing on it. The exact time needed to kill the fungus will vary depending on the oven settings, the quantity and moisture content of the marijuana, and the wattage of the microwave. There are no standards for this, but in general, smaller microwave ovens put out less power and would therefore require longer “cooking” times to kill a fungus.

Recent studies suggest that smoking marijuana may also decrease the ability of cells in the lung to destroy candida and bacteria. Candida is the fungus responsible for candidiasis, a common condition in people living with HIV. People living with HIV who smoke marijuana may be at higher risk for lung complications. This particular effect might be minimized or eliminated by baking and eating marijuana (as in pot brownies and cakes)—rather than smoking it.