Diarrhoea in pets

What It Is

Diarrhoea means stools that are looser, more watery, or more frequent than normal for that animal. Small-intestinal diarrhoea tends to produce a larger volume of soft or watery stool without much straining, while large-intestinal diarrhoea is often smaller in amount, more frequent, and may contain mucus or fresh blood. The pattern varies by species: cattle and horses with significant diarrhoea can lose enough fluid to become dangerously dehydrated within a day, while a rabbit with true diarrhoea, as opposed to normal soft cecotropes, needs urgent evaluation.

Common Causes

Sudden diet changes, food intolerance, intestinal parasites, and viral or bacterial infections cause much of the diarrhoea seen in dogs and cats. Pigs and poultry kept in groups are vulnerable to outbreaks driven by contagious gut pathogens, which spread quickly through shared water and bedding. Chronic diarrhoea in an older cat or dog can point toward inflammatory bowel disease, pancreatic insufficiency, or a hormonal disorder rather than something eaten.

When It Is an Emergency

Black, tarry, or clearly bloody stool, diarrhoea combined with vomiting and lethargy, or diarrhoea in a very young or very old animal all justify same-day veterinary care. Profuse watery diarrhoea in calves, foals, or piglets can cause fatal dehydration within hours and should never be managed at home alone. A pet that is straining without producing much stool may actually be constipated rather than having diarrhoea, and that distinction matters for treatment.

What the Vet Will Do

Expect questions about diet, travel, and any new animals in the household, followed by a fecal examination for parasites and possibly bloodwork to check hydration and organ function. Chronic or unusual cases may call for imaging, a dietary trial, or a biopsy to reach a diagnosis. Fluid therapy is often the first priority in an animal that is already dehydrated.

Home Care and Prevention

Mild diarrhoea in an otherwise well adult dog or cat that is still eating and drinking normally can sometimes be managed with a short bland diet and close monitoring. Keep fresh water available at all times, introduce new foods gradually over several days, and keep vaccinations and parasite prevention current. Any animal that seems dull, is not drinking, or has diarrhoea lasting more than a day or two should be checked by a vet rather than treated with home remedies alone.