Aims: To conduct an Ethnopharmacological survey on medicinal plants and, to make an inventory of plant species used in the treatment of Dengue Hemolytic Infection in Deshiya Chikithsa (an autochthonous traditional system of medicine) in Sri Lanka. Study Design:  This was a quantitative and qualitative ethnopharmacological survey. Place and Duration of Study: Eleven selected districts in Sri Lanka covering Western, Sothern, and Mountain hill rages of the country, between January 2018 and January 2019. Methodology: Semi-structured validated questionnaires were administered to 173 traditional practitioners in selected eleven districts of Sri Lanka. Plants were categorized based on plant parts used and method of preparation and were used to analyze and summarize the collected data. Quantitative ethnobotanical tools used to claim and prove the use of medicinal plants for Dengue Hemolytic Infection were Frequency index (FI), Use Value for one species ( ) and the species Use Value index for one informant (UVIF). Results: The survey identified 180 plant species belongs to 76 families. Approximately 33.6% of the plant species identified were used as air-dried flowers and 30.0% of plants are prepared by aqueous decoction. The most used plants were Carica papaya L. (43.9), Coriandrum sativum L. (37.0), Mollugo cerviana L. (34.1), and Zingiber officinale L. (31.2). As calculated by Use Value for one species, Carica papaya L., Coriandrum sativum L. and Mollugo cerviana L., were reported to be of the highest  value above 0.25. There were 5.5% plant species with above 0.20 of  value, and 6.1% plant species were above 0.20 species Use Value index for one informant (UVIF). This signifies the highest relative use of these plants among the respondents and the highest number of uses of those species in the treatment of Dengue hemolytic infection. Conclusion: According to the analysis, it can be concluded that medicinal plants identified in this study are reported here for the first time concerning their use for Dengue Infection except Carica papaya L. Therefore, this documented information on the medicinal plants used in Deshiya Chikithsa system of medicine in Sri Lanka may be used as baseline data for future pharmacological and phytochemical studies.