Antidiarrheals are the name given to certain types of medicines that stop or slow diarrhea. Antidiarrheals only relieve the symptoms of diarrhea, such as an increased frequency and urgency when passing stools, they do not eliminate the cause of it. This means that as soon as you stop taking an antidiarrheal, diarrhea will return unless whatever has caused it has run its course. Some antidiarrheals work by slowing down intestinal contractions, increasing the time it takes for the contents of the bowel to be excreted. This allows more water to be absorbed from the bowel back into the body, reducing the water content of the stool. Others work by bulking up the stool, increasing its volume with fiber-like substances.
Oral rehydration agents may also be termed antidiarrheals; however, these do not stop or slow diarrhea, rather they ensure excessive fluid lost during diarrhea is replaced. Other agents used to help relieve the symptoms of diarrhea include antimotility agents or antispasm...