If they're saying all you can do is give baby aspirin then I'd SERIOUSLY consider getting a second opinon from a different vet.

There are several good glucosamine/chondroiton for just for dogs and at least 1/2 a dozen true arthritis meds available from vets (although most of them will require some lab work before taking and periodically during treatment for true arthritis meds).

If the vet you have says that all that is available is baby aspirin then either your vet is not aware of the current drugs available to help alieviate arthritis pain (which makes me wonder why) or he/she is taking shortcuts in treatment. This is all assuming that you've been to the vet fairly recently and have let them know that the current aspirin treatment is not working.

Actually studies have shown that aspirin for dogs is more harmful on the organs and tend to interact with other medications more often than the arthritis meds do. Be aware that some meds do require an absitnence (sp?) period off of the aspirin before making the switch which means your dog may have to have nothing for a time period so the meds do not interact.

If you've not been back to your vet in the last 3-6 months or have not told them the aspirin is not working, then please give your vet a call.

If you have been in and have told them and that's still their response, then I'd schedule an appointment with another vet for a second opinon.