According to Business Insider, "Medicated cat shampoo needs prolonged contact with the skin to provide the maximum benefit. It may be tricky getting your cat to stay in the tub for 10 minutes, but giving the shampoo time to soak in will provide your cat with relief from irritating symptoms like itching and inflammation." The shampoo works because there are powerful active ingredients like chlorhexidine and climbazole. The best cat shampoo on the market is Douxo Chlorhexidine PS Shampoo.