ASK THE VET: Windshield washer fluid’s toxic to pets and people, too

Q: While adding windshield washer fluid to my car's reservoir, I spilled some on the ground and my dog started licking it. I sopped up the liquid before he got more than a taste, but afterward, I wondered: Is windshield washer fluid actually toxic to dogs?

A: Yes. Most windshield washer fluids are 20-30% methanol, which is toxic to dogs, cats, humans and other animals. Some windshield washer fluids are 100% methanol, and others contain additional toxic antifreeze products, like ethylene glycol.

Methanol, sometimes called wood alcohol, is colorless and flammable, and it has been described as having a slightly sweet alcohol odor. It is also found in some cleaning products, solvents, paint removers, varnishes, gasolines, "canned heat" fuels, model airplane fuels and gas-line antifreeze products.

Within 30 to 60 minutes of ingesting methanol, dogs experience lethargy, loss of coordination, disorientation, tremors, emesis, diarrhea and abdominal pain. The heart and lungs can also be affected. Humans, but not dogs or cats, can suffer blindness as well.

Methanol is even toxic when inhaled or absorbed through the skin. As with other poisons, the dose determines the severity of clinical signs. Sometimes methanol is fatal, but if aid is immediate, the pet's life often can be saved.

To prevent accidental poisoning, confine your dog inside your home whenever you refill your windshield washer fluid reservoir, store the plastic container where he can't chew it, and immediately clean up any spills.

Q: Frankie, my 15-year-old cat, has been losing weight. What could be causing this?

A: Weight loss is common among elderly cats and can even occur in the absence of disease.

A cat's caloric requirements decrease by 3% every year until about 11 years of age. After that, senior cats digest proteins and fats less efficiently, so they must ingest more calories just to maintain their weight.

Unfortunately, their senses of smell and taste dull with age, so some cats become less enthusiastic eaters in their later years.

You can help by warming any refrigerated canned food to enhance the flavor. Offer Frankie supplemental meals, and place multiple food bowls with a variety of dry foods in easily accessible locations. Consider treating him to some kitten food or another high-calorie, easily digested diet rich in protein and fat.

If Frankie still eats less than usual, he might have dental pain that makes chewing uncomfortable. Or, he could have arthritis pain that discourages him from walking a distance to his food bowl or jumping up if his bowl is on a counter. Your veterinarian can help with dental problems and arthritis pain.

On the other hand, if Frankie is eating well but losing weight, he might have diabetes or an overactive thyroid gland that's revving his metabolism. Both conditions are common causes of weight loss in older cats, and both are easily treated.

Chronic kidney disease, liver dysfunction and cancer also cause weight loss. Ask your veterinarian to examine Frankie and do lab work to determine just what's causing him to lose weight.

Lee Pickett, VMD, practices companion animal medicine in North Carolina. Contact her at

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