Phytochormones are chemical messengers playing an important role in regulation of the growth and development of higher plants. The role of growth regulators in directing the translocation and accumulation of nutnents in plants was detected. Datura Stramonium L. plants were sprayed separately with IAA (50, 100 and 200 ppm), Kinebn (5, 10 and 20 ppm), Ethrel (50, 100 and 200 ppm) and Alar (100C, 2000 and 4000 ppm). The predominant fatty acids of the seed oil were C16:0, C:5:1 and C:8:2 Also traces of remaining even-number and odd number saturated and unsaturated fatty acids were present. IAA, kinetin, Ethrel and Alar at different concentration caused an increase in the percent of stearic, palmitic, oleic and behenic acids. On the other hand, the percent of lenoleic add was decreased. Amino adds and protein contents were determined in seeds of Datura stramonium I.. plants, which were separately developed, under the effect of the different concentrations of IAA, kinetin, Ethrel and Alar. The results revealed that the seed protein comprised 17 common amino adds. The major amino acids were glycine, alanine, aspartic acid and glutamic add. Amino acids such as methionine, arginine, leucine, phenylalanine, lysine, valine and threonine were present in normal concentrations. Other essential and non-essential amino adds were present also in minor concentrations, except serine. The protein content of all treatments was higher than the control. The activity rates of these plant growth regulators on protein biosynthesis was in the decreasing order: Kinetin > Alar> IM> Ethrel. Total free amino adds were present in low concentration in all treatments.