Anise offers many nutrients which support the digestive tract. They act in an antispasmodic way so that the respective organs become relaxed. Anise can even be a preventive measure for horses that often have a colic.
Additionally this medicinal herb has healing effects for the coat: in summer times you can just lubricate it on the horse so that flys and other annoying parasite will sty off. You can mix 10-25 g into the daily hay ration- horses like the taste of anise so that they will possibly even eat refused fodder.