Dehydration happens when your cat doesn't drink enough fluid to make up for what their body is losing. Untreated dehydration is life-threatening. Cats of any breed or sex may become dehydrated, but kittens, older cats and cats with other illnesses are most at risk.

Cats become dehydrated when the amount of fluid they take into their body is less than the amount they lose in urine, faeces (poo), panting, and vomit (sickness). Mild dehydration is easily corrected when your cat drinks more. But dehydration can also be a symptom or cause of serious illness. If left untreated, severe dehydration leads to organ damage and eventually organ failure. Talk to a vet as soon as possible if your cat refuses to eat or drink and/or is unable to keep fluids down.

What to do if your cat is dehydrated

• Keep your cat in cool and comfortable living conditions; check they have multiple options of fresh clean drinking water

• Offer small frequent drinks of water to prevent gulping

• Check if your cat is still passing urine; monitor how much

• Check for severe dehydration: signs of this include dry gums, sunken eyes, dry nose, panting, extreme tiredness, skin that doesn't spring back when you lift a fold

Severe dehydration needs urgent veterinary treatment. Call a vet without delay if your cat is severely dehydrated.

Common causes of dehydration in cats

Cats become dehydrated either because they are losing excessive fluid or aren’t consuming enough to meet their needs. Often, it’s a combination of both.

Increased losses:

• Severe vomiting or diarrhoea

• Polyuria, urinating (peeing) much more than normal: may be associated with chronic kidney disease or diabetes.

• Excessive panting: fever, hot rooms or hot weather; extreme exertion.

Reduced intake:

• Water deprivation: missing, empty, insufficient or inaccessible water bowls

• Physical inability to reach water: may be due to neck pain or weakness

• Anorexia: refusing food and water

Illnesses frequently associated with dehydration include chronic kidney disease, diabetes, gastroenteritis and poisoning.

When to worry if your cat is dehydrated

Call your nearest vet if your cat:

• Has vomiting or diarrhoea and is unable to keep any fluids down

• Has not passed any urine for 24 hours

• Has signs of a blocked bladder: Struggling to pass urine and passing only tiny amounts, sometimes with blood

• Is showing signs of severe dehydration

• Is struggling to stand, wobbly or collapsed and hard to rouse

Tips to prevent your cat becoming dehydrated

• Make sure your cat has ready access to multiple options of fresh clean drinking water at all times.

• Feed a wet food diet, which is usually around 70% water.

• Keep your cat cool; ensure adequate ventilation in rooms your cat sleeps in.

• Never leave your cat in a hot car.

• Keep up-to-date with vaccinations and regular anti-parasite treatment to prevent preventable causes of vomiting, diarrhoea and serious illnesses.

How to tell if your cat is dehydrated

Ways to check if your cat is dehydrated:

• Check their gums: In dehydration, the gums are dry and sticky instead of moist. They may also be pale or dark red colour instead of salmon pink.

• Test for a skin tent: Pinch and lift a small fold of skin on their neck or forehead. In dehydrated cats, the skin stays raised like a tent instead of springing back into place.

Signs to look for:

• Dry nose; Sunken eyes

• Excessive panting; fast heart rate

• Lack of energy; sleeping more

• Passing less or no urine; dark concentrated urine (except cats with chronic kidney disease)

• Weakness, unsteadiness, difficulty getting up

• Collapse and coma

Caring for dehydrated cats at home - and when not to!

Mild dehydration

• Ensure their water bowl is topped up regularly and encourage them to take small frequent drinks. Offer water in whatever container your cat prefers - bowl, sink, your own glass!

• Offer wet food. Add water or salt free stock to food if your cat’s still eating and feed warm.

Moderate dehydration

• Offer an electrolyte replacement solution to replace fluid, sugar and salts. To make an electrolyte replacement solution at home, dissolve 1 teaspoon of household salt and 2 teaspoons of sugar in 500mls of boiled cooled drinking water.

• Offer small amounts of water or electrolyte solution every hour.

• Call a vet if your cat does not recover fully within 12 to 24 hours.

Severe dehydration

Signs of severe dehydration include sunken eyes, dry gums, panting, extreme tiredness, and skin that doesn't spring back when you lift a fold. Severe dehydration can lead to organ damage and death. It needs prompt and aggressive vet treatment. Call a vet without delay if your cat is severely dehydrated.

Vet Treatment for dehydration in cats

Emergency treatment for severe dehydration:

• Hospitalisation and monitoring

• Giving fluids directly into a vein in your cat's leg

• Sometimes giving fluids under the skin. These are used for less urgent cases, young kittens and where injecting into a vein isn’t possible; occasionally continued at home by owners under vet guidance.

Are some cats at more risk of dehydration?

Although any cat, of any breed, age or size, can become dehydrated under certain conditions, some cats are at greater risk.

• Certain age groups: Young kittens and older cats

• Very thin or overweight cats: Thin cats have little muscle to store moisture. Fat tissue holds less moisture than lean muscle.

• Cats eating purely dry food diets: Bearing in mind that a cat’s ‘wild’ diet is a mouse, which is over 90% water, it’s not surprising that cats on dry diets are more likely to get dehydrated.

• Cats living exclusively indoors: Not hunting and more likely to overheat.

• Cats with existing illnesses; such as kidney disease, diabetes, heart disease.