AniHist H was developed to help horses breathe better. All-natural support for seasonal allergies, respiratory health, normal histamine levels, and a healthy immune system in horses. Also aids your horse in combating environmental irritants and pollutants. AniHist H contains a blend of natural ingredients, including peony root, ginger, choline chloride, vitamin D, and vitamin C. Feed 1 oz. twice daily for 10 days, then 1 oz. daily. Powder.