Source: The Great Interpretation of Dreams (Ibn Sirin)
Diarrhea in a dream indicates extravagance in spending money. If it has a foul smell, it is spending on forbidden things.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
Diarrhea indicates the end of worry and recovery from illness.
Source: Signs in the Science of Expressions (Ibn Shaheen)
Diarrhea is interpreted as money. Whoever sees himself having it will lose money.