Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Diarrhea ?
    ### Response:
    Acute diarrhea is usually caused by a bacterial, viral, or parasitic infection. Chronic diarrhea is usually related to a functional disorder such as irritable bowel syndrome or an intestinal disease such as Crohns disease.
                
The most common causes of diarrhea include the following:

    