My wife and I show and breed Cavaliers and tear staining is somewhat common in our breed. It does seem to be worse in young puppies and get better as the puppy gets older. All we do is wipe the tearing every day with a damp cloth. If it really gets out of hand, one of the best products we have used is Angel Eyes or Diamond Eyes. If the staining persists, you might have the vet or opthomologist look at the eyes to be sure there is not a blocked tear duct. We also will many times see an increase in tearing when teething.

A lot of people (ourselves included) have had luck changing dog food when the problem goes into adulthood. We recommend a premium dog food. What we tell our puppy people is to go to the grocery store and see what they sell; that will tell you what NOT to buy. Then go to a place like Petco or Petsmart to buy a premium food. Every year the Whole Dog Journal publishes a list of recommended foods that is an excellent guide. You do have to subscribe, but it's a great newsletter; they are like Consumer reports in that they do not accept advertising. They have several articles in each newsletter that cover everything you can imagine about dogs. I highly recommend it.