Do japanese garlic tablets treat arthritis?

It's possible! If you ask most allopathic physicians, the answers will be no. I am an allopath too, but, being a japanese and possibly biased, I must say garlic in general with its compound called allicin does have anti-inflammatory, antioxidant, antibiotic, anti-fungal, and antiviral properties. Garlic in my opinion is underrated. It can possibly help with symptoms of arthritis.
Garlic tablets. There is no evidence that garlic tablets help arthritis. However, there are anecdotal evidence that they help. There is virtually no risk. Therefore, any benefit is more than you have now.