If their coat is dull, and full of dandruff, they don't have enough oil in their diet. Canola oil will work, however most dogs don't fancy this in their food. So good alternatives consist of such things as the grease from breakfast, or the oil that is used to preserve garlic or anchovies. Pour about a fourth a cup into the dogs food twice a day, and within three weeks their coat will be shiny and lustrous. If your dog is depressed, or overwhelmed by a new situation, honey is the most natural elixir.
Honey is also a good supplement for bad breathe.
Tearing eyes is a hereditary trait. If you dog has light fur, which gets frequently stained, there is a simple solution. First wash the dogs face and affected area very well, then pat it dry. Next brush hydrogen peroxide onto the area, pour a bit into your hand and rub it in. Leave this on the fur until the dog's next scheduled wash.