Dawn dish soap will drown fleas that are on your pet, killing them quickly. However, it does nothing to prevent reinfection with fleas, so you are likely to see an ongoing flea issue with your pet unless you switch to a proper preventative flea product.
Although Dawn kills fleas, veterinarians say it doesn’t repel them or prevent infestations. Think of it as more of a temporary fix than a permanent solution.
“Since only a small percentage of fleas are on a pet at any given time, fleas from the environment will simply hop right back on and restart the infestation cycle,” says Jennifer Coates, DVM.
Plus, flea populations can quickly grow out of control, says Dr. Reeder. “One adult flea can lay up to 50 eggs per day. Even if 10% hatch, then that would be five fleas from one female,” he says.
Dawn was not designed to be a flea repellent, let alone one that can control fleas for extended periods of time. To truly keep your pet flea-free, you need to keep up with regular preventative treatment.