Histall H is the only product I have found that had helped my horses with extreme bug allergies fight off midges. I could not find this product earlier this summer and 4 horses had ear midges so badly they lost hair outside the ears and their ears were bloody from scratching the itch. Even SSD with ivermectin did not help. Skin so soft and creamed Benedryl along with Benedryl tablets helped once they got midges but not with prevention. In September, Histall H was available again and the 4 horses have been getting it. Within one week, midges were cleared in two horses. After 2 weeks, another horse has hair on the outside and just a few scabs inside the ear but is no longer irritated by the midges. The worst case of bloody ears is slowly clearing up as I continue to give Histall H to this mare. She is no longer scratching, but she will have some scars. The Histall H allows her immune system to combat the saliva of the midges bite. Thank goodness. Histall H had given me relief, too, in dealing with the midges and sweet itch in the tail of my 21 year old gelding Live this product. Can get it for less on this site than with Chewy, just have to plan a few days ahead bc it takes 5 days if to get in the mail