A horse lover shared the following formula she used on the mane and tail of her filly: 1/3 Listerine (original formula) 1/3 baby oil and 1/3 water Put in a spray bottle, shake well and spray it on. This is quite similar to the formula recommended for dogs’ itchy hot spots. The herbal oils in Listerine may have some antifungal or antibacterial activity. Chronic itching may be the result of an allergic reaction. Changing to a hypoallergenic dog food is sometimes helpful.