Dogs love chewing on things and plants are no exception. Walnut wood is known to produce a toxic chemical and, while this chemical can cause a myriad of problems for other plants and some animals, the real concern for your pup is found in the husks of fallen walnuts.
Walnut Husks are Toxic to Dogs
Fallen walnut husks can develop a toxic mold of the penicillin derivative "Penatrim A." If ingested, this mold can cause seizures and tremors in dogs, and may even prove fatal. In addition, the wood and husks are of hard, fibrous materials with the potential to splinter. Because of this, sharp edges may cause digestive irritation and internal bleeding. If there is concern your pet may have ingested this plant, a veterinarian should be contacted right away.