From the standpoint that Tolkien didn't know any negative consequences to pipeweed, couldn't you say that there was none in Middle Earth? If you think about what would have literally happened to Gandalf after smoking for so long or that simple things like Bilbo developing a cough never happened, it's obvious that pipeweed only had good effects on the person smoking it (Clearing the mind i.e. allowing Gandalf to think or just a nice way to relax).
That's how I see it.
__________________
Son of Isildur.
|