Reducing effects of exogenous hydrogen peroxide on leaf rolling in detached leaves of Ctenanthe setosa were studied. The leaves were kept in H2O2 solutions ranging from 0 to 1 mM for 48 h and then, osmotic stress was applied for 4 h by polyethylene glycol (PEG). Degree of leaf rolling, loss of leaf water, and malondialdehyde (MDA) content were reduced by 0.2 mM H2O2. Antioxidant enzymes were induced by 0.2 mM H2O2. Endogenous H2O2 content was increased after the 0.5 and 1 mM H2O2 treatments but was decreased after 0.2 mM H2O2 treatment. Proline was decreased after exogenous H2O2 applications. Total soluble sugar content was increased as compared to the control after 0.2 mM H2O2 treatment. In conclusion, low-dose exogenous H2O2 treatment could delay leaf rolling by inducing tolerance to osmotic stress due to modulation of the antioxidant system, soluble sugar accumulation, and maintenance of leaf hydration. Therefore, postharvest life of C. setosa cut foliage could be extended by 0.2 mM H2O2 treatments.