Walnuts

Symptoms reported in cats

Most serious first.

1. 1
   Choking or Intestinal Obstruction Immediate (for choking) or progressive over hours to days (for intestinal blockage). · Because nuts are hard and difficult for a cat to digest, intact walnuts or large pieces pose a significant physical hazard. They can become lodged in the throat as a choking hazard or cause dangerous physical blockages within the intestinal tract.
2. 2
   Pancreatitis 24 to 72 hours (or progressively over a few days). · Walnuts contain very high amounts of oils and fats, which can trigger a painful inflammation of the pancreas known as pancreatitis.
3. 3
   Gastrointestinal Upset Within a few hours of ingestion. · The high fiber content and heavy amount of oils in nuts make them very difficult for cats to digest, easily leading to acute digestive distress.

Important notes

Walnuts (Juglans spp.) are not classified as chemically toxic to cats — the ASPCA lists black walnut as non-toxic to cats and its toxic principle as unknown — but they are a hazardous food that cats should not eat. The real dangers are physical and dietary rather than from a plant poison. Whole walnuts, large pieces, or hard, brittle shell fragments can cause choking or a dangerous intestinal obstruction, which may become life-threatening. The high oil and fat content is poorly digested by obligate carnivores and can cause vomiting, diarrhea, and other gastrointestinal upset, and may trigger pancreatitis (painful inflammation of the pancreas). Separately, moldy walnuts can harbor tremorgenic mycotoxins (such as Penitrem A from Penicillium mold); these are documented mainly in dogs but can cause severe tremors, ataxia, and seizures within hours of ingestion. Earlier claims that juglone is the primary feline toxin are not supported by authorities, so the practical message is: walnuts are not safe to feed, and a cat that eats a moldy walnut or shows tremors needs urgent veterinary care.

• Not chemically toxic, but not safe to feed: the ASPCA lists black walnut as non-toxic to cats with an unknown toxic principle; juglone is not an authority-supported feline toxin. Walnuts are a hazardous food, not a poison
• Mycotoxin risk: mouldy walnuts can harbour tremorgenic mycotoxins (e.g. Penitrem A) — documented mainly in dogs but can cause severe tremors, ataxia, and seizures within hours
• Physical hazard: walnut shells are hard and brittle; sharp fragments can injure the mouth and GI tract
• High fat content: large amounts may trigger pancreatitis
• If your cat ingests a mouldy walnut or shows tremors after contact with walnuts, seek veterinary care immediately