Has this helped anyone or their pet with arthritis?

I have never used it for arthritis. It has worked well for abscesses in cats and dogs, and for ingrown feather follicles in small birds. Homeopathic remedies are very specific to symptoms so different types of arthritis will require different remedies. I've used a non-homeopathic herbal remedy for arthritis and other joint injuries-Devil's claw root. I am not sure yet if it is safe for pets but works great for humans. My dog had acupuncture and acupressure treatment that alleviated her arthritis of the hip. Amazon has several great alternative health books for pets that include the info for that. Diane Stein Natural Health for dogs and cats, Dr Pitcairn's Natural Health for dogs and cats (the first title isn't exactly the same as the second I just can't find my copy right now). Are both good and easy-to-use. Four Paws, Five Directions is more in depth.

What is the difference between Silicea 200 and 30c? Do you swallow it after it dissolves in mouth?

Hello, The manufacturing processes of the C and CK scales yield products of different therapeutic applications. The Centesimal scale (the C scale) is diluted at the rate of 1 part of the previous solution to 99 parts of solvent. A different vial is used for each dilution step. We recommend the C scale for self-care, and we offer 6C and 30C dilutions in most retail locations. The C scale extends from 6C to 30C, where 6C is a low dilution and 30C is a high dilution. The Centesimal Korsakovian scale (the CK scale) is also diluted at the rate of 1 part of the previous dilution to 99 parts solvent, using the same vial for each step. The CK scale extends from 6CK to 100,000CK; 200CK is a medium dilution on that scale. Thank you

Can I use this for earache?

Silicon pushes out infections and other foreign things in the body. Idk if it will get rid of it completely, but I would guess it would help? I’m not a homeopath though