The objective of this chapter is to introduce the antidiarrheal agents. An antidiarrheal is a drug that is used to slow down or stop loose stools (diarrhea). Loperamide and racecadotril are discussed in this chapter along with their indication, dose, contraindication, precaution, adverse effect, and drug interaction. Diarrhea is the indication of loperamide. Acute diarrhea is the indication of racecadotril. Hypersensitivity, abdominal pain without diarrhea, bloody or infectious diarrhea, pseudomembranous colitis, ulcerative colitis, acute, caution in pediatric, caution in hepatic impairment, and caution in advanced human immunodeficiency virus (HIV) condition are the contraindication of loperamide.