Glucosamine is a a popular cure for osteoarthritis.  It is popularly taken with another supplement chondroitin as well. 

There are 5 forms of glucosamine:

• D-Glucosamine Hydrochloride (HCL) - Many feel the vegetable version of HCL is best as ti doesn't require stabailizers and you don't have to consume toxic shell fish.  Some forms of HCL contain shellfish.
• D-Glucosamine Sulphate 2KCl - The big argument is sulfate vs hydrochloride...  Problem with the sulfate versions are the additives which dilute the purity of the sulfate and of which could cause other problems. All sulfate sources (that I know of) come from animal sources.  There is a LOT of salt in the sulfate versions so watch out if that is concern.  Some argue the sulfate version is more effective but this doesn't seem to be backed up from the studies I've seen.
• D-Glucosamine Sulphate NaCl
• N-acetyl-glucosamine (NAG) Probably the worst form as the molecules are too large for the body to handle
• Poly N-acetyl-glucosamine (Poly NAG) -  Also not that great

Chondroitin is the popular sister supplement to glucosamine, however from my reading, the oral form of chondroitin isn't considered to be very effective (and it has side effects).  They even have glucosamine for pets!

Be careful with glucosamine as it is a shellfish product (shellfish being dirty toxic animals that cause allergic reactions), there is a link to diabetes, high blood pressure, high cholesterol and to hairloss (especially with it's sister supplement chondroitin which is probably the more suspect of the two as far as effectiveness and risk goes).

Another natural arthritis sulfur cure is MSM and this is considered not as 'dangerous' as the molecules are smaller.

• Journal of American Medical Association says glucosamine works for Osteoarthritis!  ...if they say a natural remedy works, then that says something.
• Side effects of glucosamine and chondroitin
  
• Individuals experience miraculous relief from migraines after taking glucosamine
  
• Glucosamine has luck with tomato allergies
  

Please note that many of the cures on this website are in a state of incomplete progress. To simplify, I have created a 'best natural cures' page which I believe contain the most effective, non-drug, non-surgical cures available.