Does Dawn Detergent Kill Fleas?

The Internet is awash with alternative treatments for fleas, most of which are ineffective. One common remedy is Dawn detergent to kill fleas on kittens who are too young for traditional flea treatments.

Does Dawn detergent kill fleas?

Yes, it does there are two ways this happens. Fleas have an exoskeleton, that is, their skeleton is on the outside of their body which enables them to float in water. Dawn works by reducing the surface tension of water (which makes it a surfactant). By doing so, fleas sink into the water and drown.

The exoskeleton has a waxy layer that protects water from entering the respiratory system. Detergent can penetrate the waxy coating on the exoskeleton, which allows water to enter the external openings called spiracles, which deliver air to the trachea and suffocate the flea.

Other brands of detergent

Dawn detergent is an American brand, blue Dawn (original) is the best type to use on your cat. Most dishwashing detergents (i.e., the kind you put into the sink, not the detergents used in dishwashers) are suitable to use if Dawn is not available. That includes Morning Fresh (Australia), Palmolive and Fairy Liquid (UK) which are all safe to use on cats.

Remember that the flea life cycle consists of four stages; egg, larvae, pupae and adult flea. The adult flea accounts for only 5% of the flea population, and if a pet owner treats only the adult flea, the cycle will continue. Dishwashing detergent is a good way to kill fleas on kittens who are too young to be treated with an insecticide. But pet owners must also treat the home, which includes bedding and deep cleaning to remove the remaining life-stages of the flea.

How to kill fleas with Dawn

Bathe the cat

  • Fill a sink with warm water and two teaspoons of Dawn (or another type of dishwashing detergent) and bathe the cat.
  • Rinse thoroughly to remove all detergent residue.
  • Wrap on a towel to remove excess water and place the kitten in a warm room. Kittens are unable to regulate their body temperature, so the kitten must stay warm.

Flea comb method

  • Fill a bowl with Dawn and warm water.
  • Carefully remove fleas from the kitten’s coat and drop them into the bowl of water to drown the flea.


Dawn and other dishwashing detergents are designed to cut through greats. When a cat is bathed in water that contains detergents, the healthy oils in the skin can dry out so pet owners must avoid using this method repeatedly.

Once a kitten is old enough, which is usually from 6 weeks, speak to your veterinarian for recommendations on safe and effective flea treatments.

Related: Quick guide to flea control products


  • Julia Wilson, 'Cat World' Founder

    Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio