Large-diameter hail is unusual in the lowland tropics; consequently, its impact on water flux responses of trees and lianas due to foliage loss is unknown. In December 2012, Xishuangbanna Tropical Botanical Garden (21 degrees 55 ' N) in southern Yunnan, China, experienced the most severe hailstorm in approximately 30 years, with hailstones of 8- to 17-mm diameter falling for 10-30 min. We assessed the effect of this hailstorm on sap flux density (SFD) in response to foliage loss in six tree and three liana species. Among the trees, for a given atmospheric vapour pressure deficit (VPD), Tectona grandis and Dipterocarpus tuberculatus showed a significant reduction in sap flux density and water use during the post-hailstorm week in comparison to pre-hailstorm week. In contrast, a liana Ventilago calyculata showed a significant increase in SFD during the first post-hailstorm week, whereas the other tree and liana species showed no significant change in their SFD and water use. T. grandis also showed visible wilting during the first 5 days post-hailstorm. However, this tree species showed recovery from wilting and also no more reduction in SFD after similar to 7-9 days. D. tuberculatus also showed SFD recovery a week post-hailstorm. We conclude that the impact of a heavy hailstorm on the water flux of tropical trees and lianas was mild or neglectable. Our study documented a rare severe hailstorm occurrence and its impact on ecosystem processes of tropical forest and enhances our understanding about water flux of tropical woody species exposed to hailstorm.