Because pecans as well as most other types of nuts tends to cause gastrointestinal distress in most dogs, it is highly recommended that you refrain from giving yours any. Although not all dogs respond the same way to nuts, chances are your dog will have problems with upset stomach, gas, or diarrhea if you give it to them.
If your dog does not have any visible adverse reactions though, you can feel free to give them pecans in moderation. Since nuts are not a natural part of a dog’s diet, you should definitely limit the amount that you give them.