Diarrhoea is a change in consistency and increases in the frequency of stools as compared to normal days. It is an indication of some underlying disease generally. It needs urgent management as there is a loss of excess fluids and salts with each episode of loose stools. It is generally caused as a result of microorganisms that act on the inner lining of the intestines and produce substances that affect the movement and reduce the absorption of water and salts from the intestine. Sometimes it may also happen due to a defective immune system where the body acts against its organs or due to excessive use of antimicrobial agents, which may even kill the good bacteria present in the gut.