Effects of the three nitrogen sources (namely, ammonium nitrate, ammonium sulphate and urea) each at the rates of 0, 50, 100 and 200 kg/fed., on vegetative, yield, anatomical characters and chemical constituents of damsisa plants were studied. The experiment was carried out as a pot experiment in Faculty of Agriculture, FayoumUniversity during the two successive seasons (2006/2007 and 2007/2008). The results obtained showed that, all sources of nitrogen fertilizer greatly increased growth parameters. All treatments (mainly, urea and ammonium sulphate) greatly increased chlorophyll a, b, carotenoids in the leaves and total carbohydrates, N, P and K contents of herb.               All treatments (especially, ammonium sulphate) increased stem section diameter, due to the increase in paraenchymatous and vascular tissues. All N sources greatly increased section diameter of leaf petiole, midvein thickness, blade thickness and dimensions of the vascular bundle as well as diameter of xylem vessels. Treating plants by ammonium sulphate greatly increased total sesquiterpene lactones. The greatest increase was observed on most previous botanical characters by ammonium sulphate. Thus, it can be recommended to use ammonium sulphate as nitrogen fertilizer for improving a yield and quality of damsisa plants under sandy soil conditions.