Christians? Is this sinful????????????????

I've asked several questions leading up to this. From a majority of Christians, I've determined that drinking in moderation is ok, as long as it doesn't control you. I've learned that taking advil or tylenol for a headache is ok. Now, I've been told that smoking weed is sinful. Besides the fact that it's illegal, what is sinful about it? If it's a pain reliever, like tylenol and advil, shouldn't we be able to smoke it for relief as long as it doesn't control us? Tylenol can do damage to the body just like weed can, if not more.What do you think? I want a Christian point of view on this so atheists need not apply. Thanks and God bless.