Wikipedia: White chocolate is a type of chocolate based on cocoa butter without the cocoa solids. It also includes milk solids, sugar, lecithin, and flavorings (usually including vanilla). Cocoa butter is the ingredient used in other chocolates so that they remain solid at room temperature yet melt easily in the mouth. Thus, white chocolate has a texture like that of chocolate but does not have the same taste. Unlike chocolate it does not contain caffeine. ========================================================= I wouldn't imagine it would be good for a dog, but a small amount probably wouldn't do more than give them the runs.
white chocolate is still poisonous to dogs, but not as much as chocolate because of the degree of cocoa in it. Darker chocolates and chocolates with high percentages of cocoa are most poisonous, then milk chocolate, then white.
White chocolate: 200 ounces per pound of body weight. It takes 250 pounds of white chocolate to cause signs of poisoning in a 20-pound dog, 125 pounds for a 10-pound dog.
Milk chocolate: 1 ounce per pound of body weight. Approximately one pound of milk chocolate is poisonous to a 20-pound dog; one-half pound for a 10-pound dog. The average chocolate bar contains 2 to 3 ounces of milk chocolate. It would take 2-3 candy bars to poison a 10 pound dog. Semi-sweet chocolate has a similar toxic level.
Sweet cocoa: 0.3 ounces per pound of body weight. One-third of a pound of sweet cocoa is toxic to a 20-pound dog; 1/6 pound for a 10-pound dog.
Baking chocolate: 0.1 ounce per pound body weight. Two one-ounce squares of bakers' chocolate is toxic to a 20-pound dog; one ounce for a 10-pound dog.
Don't know how it affects dogs but I was watching FoodNetwork last night Iron Chef show and the surprise ingred. they had to use was chocolate, they had to use it in three main course meals and 2 desserts. They could use any kind of chocolate and Alton made mention of white chocolate and how it was made from cocoa butter and sugar. That is about all I can tell ya about white chocolate and that I enjoy eating good white chocolate once in a while but I prefer good milk chocolate myself.