Application of ethephon on the bark of mature trees of Hevea brasiliensis is widely practiced to increase the rubber yield where the volume of latex harvested per tap per tree is enhanced considerably. As a result, the drain of carbohydrates and minerals alongwith the latex is increased in the trees applied with ethphon. An experiment was conducted in which ethephon was applied on virgin trees of clone RRII 105 and estimated the concentration of sucrose, Pi, Mg++, K+ and Cu++ in the latex. Concentration of sucrose in the latex was less in ethephon treated plants than control while Pi, Mg++, K+ and Cu++ were more in the latex. When the total drain of these components per tree was computed for the entire experimental period, the loss of sucrose, Pi, Mg++, K+ and Cu++ were 21, 400, 186, 68 and 67 per cent, respectively, more in ethephon treated plants than untreatd control.