Marijuana does do damage to your lungs, puts a strain on your cardiovascular system, and impairs certain functions of the brain, but alcohol does all this and a HELL of a lot more. Also, the withdrawal of alcohol alone can do more damage to your heart than smoking marijuana. With that being said, Marijuana IS a drug (well THC is actually lol), and it is addictive IF you use it multiple times a day for a month or more.