Abstract: A polysaccharide-concentrate obtained from plant of the genera Cucurbitaceae, Papilionaceae, Tiliaceae, Labiate, Malvaceae, Asteraceae, Umbelliferae, Rutaceae, Chenopodiaceae, Linaceae, Rosaceae and Plantaginaceae by extraction with water and precipitation of the polysaccharide with alcohol or acetone, if desired after further purification. The polysaccharides having a molecular weight between 75,000-2,000,000, containing maximum 5% of nitrogen, maximum 5% of phosphorus (expressed in P.sub.2 O.sub.5), maximum 25% of ash, minimum 30% of reducing sugar, minimum 60% of total sugar (after acidic hydrolysis, expressed as glucose) has been shown to have especially anti-inflammatory activity.