Plus, when it’s time to see a doctor.

Imodium usually starts easing diarrhea within an hour. The active ingredient, loperamide, reaches peak levels in about two and a half hours when taken as a liquid, and around five hours when taken as ...

Medically reviewed by Anju Goel, MD Key Takeaways Diarrhea is often contagious, especially when it's caused by viruses, bacteria, or parasites. Infectious diarrhea can spread by not washing hands ...