Pistachios tends to create more downside than benefit in canine diets.
Quick call
Best to skip it. High fat, shells, and potential mold exposure make pistachios risky.
What matters most
Do not feed pistachios; choose safer nut-free treats.
When to call your vet
If your dog has vomiting, diarrhea, unusual fatigue, or belly pain after eating pistachios, call your vet the same day.
Urgent: If your dog already ate this food, call your veterinarian or ASPCA Animal Poison Control (888-426-4435) now.
Source check: PetMD and AKC caution against pistachios because of fat load and shell hazards. Source