Although cashews don't immediately harm dogs, they should only be given occasionally and in small quantities. Cashews have a significant amount of fat, and too many can cause health problems, including an inflamed pancreas. Too many cashews can also lead to weight gain, which is connected to many health issues.
Nuts are usually safe for dogs to eat, but some varieties can cause problems. Macadamia nuts should always be avoided because they are very toxic to dogs, even in small quantities. Walnuts and black walnuts can also be toxic to some dogs. Almonds are safe, but some dogs may have problems digesting them. Any type of nut with mold should be immediately discarded.