If food contains unhygienic elements, it will cause diseases.  Usually unhygienic food can cause gastrointestinal disorders, such as abdominal pain, vomiting and diarrhea. If food is contaminated with parasitic ovum, it will cause various parasitic diseases. Putrid food is poisonous and can cause acute abdominal pain, vomiting and diarrhea if it is taken.

Unhygienic water is also a pathogenic factor. The natural source of water in a industrialized society is often contaminated with various poisonous or harmful elements. Drinking such water can also lead to various acute or chronic diseases due to water poisoning.