Why 3 kg turns a handful into a crisis
Cats lack certain liver enzymes that help dogs process theobromine slightly better — combined with your cat's tiny 3 kg frame, this creates a perfect storm. A 'small handful' to you is a massive dose relative to her body size. Unlike dogs that might vomit proactively, cats often retain the toxins longer because they're less likely to purge naturally. Her grooming habits mean she's probably ingested more than what initially went into her mouth.
Even if the mulch looks partially decomposed, theobromine persists through composting. Indoor cats are especially vulnerable because they haven't built up any tolerance to outdoor toxins. Her metabolism will treat this as a foreign chemical invasion — hence the high risk of neurological symptoms before gastrointestinal ones appear. Size isn't just a factor here; it's the dominant variable.
The silent progression in feline toxicity
Where dogs often show early vomiting or restlessness, cats may initially seem lethargic or withdrawn — easy to mistake for napping. Watch for dilated pupils that don't constrict in light, excessive vocalization, or sudden clumsiness knocking over objects. These subtle signs often precede the more dramatic tremors or seizures cats experience at lower toxin thresholds than dogs.
Their heart rhythms are particularly vulnerable — cats can develop dangerous arrhythmias without obvious outward symptoms. This is why waiting is never safe, even if she 'seems fine.' The handful she ate likely contained concentrated cocoa shell fragments that deliver more theobromine per gram than some chocolate bars. Her small body has nowhere to distribute that safely.
How indoor status changes the equation
Outdoor cats sometimes develop slight tolerances to plant toxins, but your indoor cat has zero defenses against this exposure. Her liver isn't primed to handle unexpected chemicals the way a scavenging cat's might be. This makes her reaction potentially more severe even compared to another 3 kg cat who goes outside.
Check her litter box — if the mulch contained additives like fertilizers or mold inhibitors, those could appear in her urine or stool before theobromine symptoms do. Indoor cats also tend to be less active than outdoor ones, meaning slower circulation that may delay symptom onset but prolong exposure. Don't assume safety because she's not showing classic 'dog' reactions — feline toxicity follows different rules.
Immediate actions while seeking help
Confine her to one room with water but no food — voluntary drinking helps, but forced fluids risk aspiration. Remove any strings, toys, or objects she could tangle in if seizures start. Cats often hide pain, so assume she's more affected than she appears. Brush any visible mulch particles from her coat to prevent further ingestion through grooming.
Note her respiratory rate (normal is 20-30 breaths per minute at rest) — rapid breathing or open-mouth panting in cats always signals distress. Have her carrier ready with a familiar blanket inside; stressed cats resist handling, and you'll want to move quickly if her condition changes. Time matters more than visible symptoms at this size — theobromine works silently in small bodies.
The step-by-step response, from the first minute to the vet visit, is in our Cocoa Mulch Poisoning in Dogs and Cats emergency guide.