Nerve damage. Dry mouth can be a result of nerve damage to the head and neck area from an injury or surgery. Dehydration. Conditions that lead to dehydration, such as fever, excessive sweating, vomiting, diarrhoea, blood loss and burns can cause dry mouth. Surgical removal of the salivary glands.
Ethnopharmacology is a related study of ethnic groups and their use of drugs. Ethnopharmacology is distinctly linked to plant use, ethnobotany, as this is the main delivery of pharmaceuticals. Ethnopharmacy is the interdisciplinary science that investigates the perception and use of pharmaceuticals within a given human society.
An ethnography is an account of a particular people. Ethnology is the systematic collection, comparison, and contrast of ethnographies. So ethnography is specific, ethnology is generic. Another way to look at is that writing or collecting ethnographies is something anyone can do, but ethnology is a specific academic discipline, another name for cultural anthropology.