The two cultivars of Ricinus communis L. (Euphorbiaceae); red Hendi 21(RH21) and green Hendi 12 (GH12) were investigation of their phytoconstituents using standard methods. Eighteen and thirteen volatile compounds were identified from the n-hexane extract of RH21 and GH12, respectively by using gas chromatography-mass spectrometry (GC/MS). The monoterpenoids; 1,8-cineole, camphene and α–thujone and the sesquiterpenoids; β- caryophyllene and longifolene were detected in both cultivars. Whereas, the monoterpenoids; camphor and α - pinene were found only in RH21. In addition the biochemical composition of minerals, protein, lipids, carbohydrates and the quantitative evaluation of the total content of phenolic, flavonoids, anthocyanins, tannins, and alkaloids were studied. Gallic acid, epicatechin, quercetin and kaempferol are the major phenolic compounds detected in the aerial parts of each cultivar in variable amount. The stable free radical scavenging activity (FRSA) of both cultivars was determined using the 1.1-diphenyl-2-picryl-hydrazil. Variable primary metabolites content in both cultivars was reported. The cultivar RH21 had the superiority in the contents of all the investigated secondary metabolites and FRSA than the GH12 cultivar. The potential of the cultivars crude extracts were bioassayed to determine their acaricidal activities against the mite Tetranychus urticae Koch using dipping and spray methods. The cultivar RH21 had high mortality on the larvae and adult females of T. urticae than GH12. The results of this study suggest that the natural product derived from the red cultivar RH21 of R. communis may has potential use as acaricidal agent. This activity of RH21 might be attributed to the presence of various bioactive phytochemicals.