[WARNING!] Please only use shampoo, and flea treatments with neem oil in it for cats. NEVER give your cat a flea dip. The chemicals in this will kill your cat. If you are going to treat for fleas, give a flea bath in warm, cats feel heat more than we do so not too warm, water with some natural soap in the water. You can add neem oil to this soap. If the infestation is bad apply directly to the coat, but rinse well, as the soap film in the fur can cause vomiting.
Replied by Rfb