Because cats are such conscientious self-groomers, you may not think you'll ever need to bathe them, but there will be times when your kitty needs a little assistance.

The first step is knowing what to bathe a cat with. Do you need cat shampoo, or can you use your own shampoo? What if you have a dog — can you use dog shampoo on cats?

When it comes to bathing your feline friend, it's important to use a shampoo that's specifically formulated for cats. Read on to learn why, and find out how to choose a shampoo for your cat.

Bathing a Cat: What Not to Use

Cats can get all kinds of stinky and dirty. If they rummage around in a potentially dangerous substance, such as motor grease or foods that are toxic to cats, or if they have fleas or ticks, it's time to prep a cat bath. They aren't going to like it, but keeping your cat clean is essential to their health.

During a bath, you don't want your kitty to ingest any toxic ingredients, and you certainly don't want to use a product that may cause harm, so avoid shampoos that aren't formulated for felines.

Can You Use Dog Shampoo on Cats?

If you have both a cat and a dog at home, it's easy to think that your dog shampoo can do double-duty, but certain ingredients in dog shampoo are harmful to cats.

For example, many of the ingredients in flea-killing dog shampoos and treatments are safe for dogs but can be very toxic to cats, cautions International Cat Care. Permethrin, in particular, is especially dangerous for cats, because a "cat liver lacks certain proteins (enzymes) that break down some chemicals into harmless forms, meaning that the chemical can accumulate in the cat's body and cause serious illness," says International Cat Care. Permethrin is a synthetic form of the substance pyrethrin, derived from the chrysanthemum flower. You may find this ingredient in very small doses in some cat treatments, but it's best to avoid them all together.

Can you use dog shampoo on cats who have dandruff? Similarly, shampoo for dogs with dandruff may contain ingredients — even naturally derived ones — that are harmful to your cat. If your cat has fleas or a skin condition such as flaky skin, consult with your veterinarian about safe and effective shampoo options.

Can You Use Human Shampoo on Cats?

Put simply, you should never use human shampoo on cats (or dogs), states Preventive Vet, because it can "cause inflammation and irritation of your pet's skin." This, in turn, causes more itching and can lead to skin infections. These negative skin reactions occur because human shampoo is formulated for humans, who have a different pH level (the scale of acidic to basic compounds) than cats.

Some harmful ingredients in humans shampoo include parabens, sulfates (ammonium laureth sulfate is common), isopropyl alcohol, coal tar and certain preservatives, some of which can lead to kidney and liver damage. Even baby shampoo can be too harsh for cats, points out Cat Health.