Horehound (Marubium vulgare) is a dietary supplement. Traditionally Horehound is suggested for use in:- 
 
Digestive problems including diabetes, loss of appetite, bloating, gas, diarrhea, constipation, liver and gallbladder complaints.
Respiratory issues including cough, whooping cough, asthma, tuberculosis (in the past), bronchitis and swollen breathing passages.
Women use horehound for painful menstrual cycles.
 
Horehound is -
Approved for treatment of bronchial problems and as an appetite stimulant by European Medicine Agency and the German E Commission—an advisory group on herbal medicines.
Approved as a safe food additive by the U.S. Food and Drug Administration (FDA), however, has declared horehound ineffective for use as a sore throat remedy.