I don’t believe there is any evidence that smoking marijuana makes the immune system stronger – that is, able to better fight off infections.
Smoke of any kind will cause lung damage, and is likely to make you more susceptible to lung infections. There is some evidence that pot smokers suffer from increased rates of chronic bronchitis[1] , but marijuana smoke appears to be less toxic than tobacco smoke[2] .
There is a fair amount of evidence that marijuana is immunosuppressive – cannabinoids inhibit a number of immune functions in test tubes, including the ability of immune cells to kill viruses and bacteria, produce antibodies, and to migrate to sites of infection. Susceptibility to bacterial and viral infections is increased in several animal models[3] . But evidence of real-world susceptibility to infection among humans is lacking.
Given its immunosuppressive effects, marijuana may have therapeutic value in combatting inflammatory bowel disease[4], rheumatoid arthritis[5] and autoimmune diseases[6] .
But don’t smoke pot thinking that you are warding off infections. The opposite is more likely to be true.
Footnotes
[1] Adverse Health Effects of Marijuana Use
[2] Effects of marijuana smoking on the lung.
[3] Effects of Cannabinoids on T-cell Function and Resistance to Infection
[4] Cannabinoids for treating inflammatory bowel diseases: where are we and where do we go?
[5] The endocannabinoid system and its therapeutic implications in rheumatoid arthritis.
[6] Cannabinoids and autoimmune diseases: A systematic review.