Twenty two medicinal plants have been observed to be affected from nine species of Alternaria of various nature. Alternaria alternata, a plurivorous fungus, of wide spread occurrence infected almost all the medicinal plants except only three of them. Three distinct species of Alternaria are involved in causation of three different types of diseases in Datura. Species of Alternaria like A. crassa, A. papevris, A. panax and A. longipes specifically are found to be associated with their respective hosts only. Alternaria solani is the species restricted only to infect the host plants of family Solanaceae proved true to cause the leaf spot diseases in Sarpgandha (Rauwolfia serpentina), tomatilo (Solanum khasianum) and Ashwagandha (Withania somnifera). A. tenuissima was found associated with four medicinal hosts.