Why two stale peanuts are unlikely to harm your 5 kg cat
The small amount your cat ate is the main reason this isn't an emergency. Two peanuts contain minimal aflatoxin even if mould was present, and a cat this size would need to consume far more to risk liver damage. The harder concern is whether these nuts were rancid—old fats can irritate the stomach lining, leading to digestive upset rather than poisoning.
Since peanuts were dry-roasted or raw (not coated in salt or seasoning), the primary effects would be local irritation. Watch for lip-licking, drooling, or repeated swallowing over the next 2–4 hours as signs of nausea. If those appear, withhold food but keep water available to help flush the system.
How to check for mould-related risks with floor-found food
Peanuts left in humid environments for a week may develop invisible mould. While you can't test this now, know that acute aflatoxin poisoning shows as sudden loss of coordination or yellow gums—both extremely unlikely here. More probable is mild lethargy if the fats caused indigestion.
Inspect the area where the peanuts were found. If there's visible mould or a musty smell, monitor your cat closely for 24 hours. Any vomiting with bile (yellow foam) warrants a vet call, as it suggests prolonged stomach irritation.
The 12-hour window when digestive symptoms typically appear
Most reactions to old peanuts happen within half a day. Your cat may seek out grass to eat or have one episode of loose stool. This is the body's way of expelling irritants and isn't alarming unless it persists beyond two bowel movements.
Hydration matters more than food right now. Offer a ice cube to lick if your cat refuses water. The cold can soothe throat irritation from any nut particles stuck during swallowing. Avoid milk or broth, which could worsen stomach upset.
When leftover snacks become a vet visit for cats
Two scenarios would justify calling your vet: if your cat hasn't urinated in over 12 hours (possible dehydration from vomiting) or if it presses its head against walls (a neurological red flag). Neither is expected from this tiny quantity.
For peace of mind, weigh your cat in three days. A loss of over 5% body weight (250g for a 5kg cat) could signal prolonged nausea affecting eating. Otherwise, those stray peanuts were probably just a gross but low-risk snack.
The full verdict, portion guidance and serving notes are collected on the Peanuts food facts page.