Acute diarrhoea in cats: red flags that require investigation
2-year-old indoor cat with diarrhoea for 2 days. His food was changed a week ago.
Which of these findings justifies moving from symptomatic treatment to a diagnostic work-up?
chevron_right Show answer and explanation
A. Lethargy, moderate dehydration and pain on abdominal palpation
Correct. These are signs of complicated diarrhoea: they require ruling out obstruction (linear foreign body, intussusception), panleukopenia, pancreatitis or peritonitis with bloodwork and imaging, and treating with IV fluids.
B. Soft faeces with some mucus and fresh blood in a bright cat
This suggests mild acute colitis. If the cat is bright, eating and hydrated, it can be treated symptomatically and reassessed.
C. The diarrhoea having lasted 48 hours
Acute diarrhoea is defined as lasting less than 2–3 weeks. Two days' duration in a stable cat is not a red flag on its own.
D. A history of a recent change of diet
On the contrary: a clear dietary trigger supports uncomplicated diarrhoea, which usually resolves with a digestible diet.
lightbulb Key takeaway
Before treating symptomatically, always examine and palpate the abdomen and look under the tongue (linear foreign body). Fever, repeated vomiting, lethargy, pain, dehydration or an unvaccinated kitten turn acute diarrhoea into complicated diarrhoea.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.