Bhoot Vidya or Graha Chikitsa
This branch of Ayurveda deals with diseases acquired from apparently unknown causes. In modern terminology it can be considered as idiopathic diseases in which the exact cause of disease is unknown.
This branch of Ayurveda deals with the effects of various super-natural forces on the person. This description can be correlated with bacterial or viral infections. Moreover, the description of usage of several disinfectant plants for fumigation, to make the atmosphere germ free also supports this correlation. It has been correlated with psychiatry as well.