Seeds of Ricinus communis L. [Euphorbiaceae] constitute a source of a fatty oil which is widely used as a valuable article of medicine and commerce. As no study has been reported, sofar, the present study could be the first to deal with the phenolic patterns of R. communis, growing in Saudi Arabia, which resists the environmental stress and have medicinal significance. The study was also conducted to demonstrate a comparative autecological study of the plant growing in Bani Kobir, The Ain, and in Al-Taif. Some physical and chemical analyses of the soil were determined [soil type, soil pH, electrical coductirity [EC], water content, and organic matter content]. Some soil minerals were detected. The isolated bacteria form the rhizosphere were Cocii and Bacili whereas the isolated fungi were Aspergjllus and Pencillm. The insects around the plant followed different families and orders. Flavonoids were classified according to their chemical structure to three groups: O-Flavonols including quercetin; rutin; quercetin-3-glucoside; quercetin 3-glucoside; and Kaempferol, O-Flovones, apigenin; C-Flovones; vitexin. O-Flavonols were the predominant. O-Flavones were represented by a free aglycon only. Apigenin was accompanied by its C-Flavone; vitexin. Both condensed and hydrolysable tannins were detected. Three phenolic acids were detected; 2,5-dihydroxybenzoic acid, Chorogenic acids, and 3,4,5 trihydroxybenzoic acid. The latter is the precursor of hydrolsable tannins [+]catechin; the flavan derivative and [-]-epicatechin; the precursor of condensed tannins were detected of phenolics in plant tissues.