Why mould poses more risk than basil for a 5 kg cat
Those two wilted basil leaves likely harbored mould spores that began producing toxins as the plant decayed. For a cat weighing just 5 kg—especially an older one—even small amounts of mould can irritate the digestive tract or, in rare cases, affect the nervous system. Fresh basil would be harmless, but decomposition changes the equation.
Different mould species produce varying toxins, some causing vomiting within hours, others triggering subtle neurological signs like wobbliness or dilated pupils over days. Without knowing the mould type, it's smart to monitor her closely for any abnormal behavior beyond typical post-snack napping.
The critical 24-hour observation window
Watch for frequent lip-licking, retching, or actual vomiting—the first signs usually appear within 6-12 hours if mould toxins are present. Senior cats may show more subtle symptoms like hiding or refusing favorite treats. Check her gums for unusual paleness or tackiness, which could indicate dehydration from fluid loss.
Offer fresh water in a wide, shallow bowl to encourage drinking, but don't force it. If she shows no interest in water by the 12-hour mark or hasn't urinated normally, that warrants a vet visit. Normal grooming and curiosity about food are good signs she's weathering the exposure well.
When to bypass monitoring and call the vet
Any twitching, muscle tremors, or difficulty walking means she needs immediate veterinary care—these suggest neurotoxins are affecting her system. Similarly, vomiting more than twice in an hour or producing diarrhea with visible blood requires prompt attention for fluid support and anti-nausea medication.
For a senior cat, even mild lethargy that persists beyond a nap cycle merits a check-in with your vet. Older organs process toxins less efficiently, so early intervention prevents minor issues from escalating. Bring photos of the mouldy leaves if possible to help identify potential toxins.
Preventing future mould ingestion at home
Store fresh herbs in airtight containers in the fridge, where they'll stay crisp for days. Cats often target wilted plants because the softened texture is easier to chew, so discard aging produce promptly. Consider growing a small pot of fresh cat-safe greens like wheatgrass to divert her interest from cooking ingredients.
If your cat frequently scavenges discarded food, use a lidded compost bin placed well out of reach. Some moulds produce spores that become airborne when disturbed, so clean the area where the leaves sat with a pet-safe disinfectant to remove residual particles she might encounter later.
The full verdict, portion guidance and serving notes are collected on the Basil food facts page.