There is a huge amount publicised about the Medicinal effect of Marijuana on Arthritis and similar related disorders to which AS fits in.

Word of warning with smoking:

I used to smoke it when I was much younger & it helped to relax me and alleviate inflammation, but I found that smoking it would lead to chronic chest infections which brought with it intense flair ups. After a long time without it, I have come back out of retirement & I now use it if & when I get a flair up. I will either bake with it or use a vaporiser. I would strongly advise either - they are a much healthier way to consume it, and really helps me when I have a bad day.