Documentation of indigenous knowledge system on medicinal tree resources was made in a total of 10 tropical dry evergreen forest areas. A total of 172 medicinal-use information was recorded for the treatment of 37 ailments. Significant proportion of medicinal plants was used to treat wounds, skin diseases, stomach-ache and dental diseases. Protection of tropical dry evergreen forest patches is not only conserves local biodiversity but also protect traditional herbal knowledge of indigenous people and herbal practitioners. The present study contributes significant amount of information on medicinal and non-medicinal uses of trees to ethnobonical databases of Nagapattinam and Thiruvarur districts, Tamil Nadu.