Hemicellulosic moieties from opium poppy and cotton stalks were solublized in water at varying alkali concentrations (NaOH) and peroxide (H2O2). The hemicelluloses were then be precipitated from the solutions by acidification. The 2.0 and 3.0% H2O2 extractions resulted in a yield of 0.8 and 0.71%, respectively, accounting for 3.2 and 2.9% of the hemicelluloses present in the opium poppy stalks. A similar result was also obtained for cotton stalks. It was found that alkaline peroxide is an effective agent for solubilization of hemicelluloses from opium poppy and cotton stalks.