Can Cats Eat Sultanas (dried grapes)? The Full Answer
Cats are obligate carnivores and have zero nutritional requirement for fruit of any kind. Sultanas are dried grapes—the drying process concentrates the toxic compound (identity still unknown as of 2026, despite decades of research) responsible for acute tubular necrosis and glomerulonephritis in cats. A single sultana contains roughly 3–4 times the nephrotoxin concentration of a fresh grape, making sultanas proportionally more dangerous. Studies in both cats and dogs have identified a dose-dependent nephrotoxic response, but the threshold varies widely between individuals—some cats tolerate one or two raisins with minimal damage; others show severe kidney failure from a single fruit. This unpredictability makes any sultana consumption a medical emergency.
The toxin mechanism remains unclear. It is not cyanide, oxalate, or known plant alkaloid. It does not cause acute oxidative damage (as some theories suggested early). The compound appears to trigger direct nephrotoxicity via glomerular basement membrane disruption and tubular necrosis. Onset of symptoms typically occurs 24–72 hours post-ingestion; early treatment (within 24 hours) with activated charcoal and IV fluids offers the best prognosis, but delayed presentations (>72 hours) frequently result in permanent renal damage or death despite aggressive intervention.
Drying concentrates the toxic compound further, making sultanas more dangerous gram-for-gram than fresh grapes. A single sultana (approximately 1g) may contain the same nephrotoxic load as 2–3 fresh grapes. For a 4kg cat, eating even 2–3 sultanas represents a potentially lethal dose.
How to Safely Serve Sultanas (dried grapes) to Your Cat
- **DO NOT SERVE**—keep all sultanas, raisins, and dried grapes inaccessible
- Store sultanas in sealed containers away from cats
- Check ingredient lists of cereals, trail mix, baked goods, and commercial pet treats
- Do not allow cats access to compost (where dried fruit may be discarded)
- Keep rubbish bins secure to prevent scavenging
Frequently Asked Questions
What's the difference between sultanas, raisins, and currants? Are any safer?
All are dried grapes and equally toxic. Sultanas, raisins, and currants all contain the same nephrotoxic compound. None is safer.
My cat ate a single sultana from a dropped piece of food. What should I do?
Contact your vet immediately—do not wait for symptoms. Bring the sultana package if available. Even a single sultana is a medical emergency.
How long after eating a sultana do kidney symptoms appear?
Symptoms typically appear 24–72 hours post-ingestion. Some cats show no signs until 48+ hours when irreversible damage may have occurred.
Can my vet fix kidney damage from sultana toxicity?
If treated within 24 hours, activated charcoal and IV fluids can prevent or minimise damage. After 72 hours, kidney damage is often permanent.
Are dried grapes in commercial cat treats or cereals a risk?
Yes. Many human cereals and some pet treat formulations contain raisins or sultanas. Always check ingredient lists.
