||In this study, the in vitro cytotoxicity and antioxidant properties of the ethanolic and alkaloidic extract of Delphinium Staphisagria seeds were assessed. The antioxidant activity of the plant extracts and the standard was assessed on the basis of the radical scavenging effect of the stable 1, 1-diphenyl-2-picrylhydrazyl (DPPH)-free radical activity. The in vitro cytotoxicity was carried out by using the 3-(4,5- dimethylthiazol- 2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, against two animals cancer cell lines; Vero cell line, initiated from the kidney of a normal, adult African green Monkey and Neuro-2a (N2a) from a spontaneous tumor of a strain A albino mouse. The DPPH scavenging activity of both extracts was concentration-dependent (increasing from 15.62 µg/ml to 500 µg/ml), exhibited considerably (P<0.05) DPPH radical-scavenging activity and was able to inhibit the formation of DPPH radicals with a percentage inhibition of 62.19 and 94 % respectively at the highest concentration. The results showed that the alkaloidic extract (1000-31.25 µg/ml) of Delphinium Staphisagria possesses significant IC50 compared to the drug positive control on all cancer cell lines used. The lower IC50 represent the highest potency of a compound to inhibit the growth of cells and cause toxicity and death of cells. The result obtained in this work demonstrated a high activity at low alkaloids extracts doses (500µg/ml). In conclusion, the results of the present study suggest that Delphinium Staphisagria seeds plant have various secondary metabolites and has good quantity of alkaloidic compounds (diterpenoid alkaloids). Plant has potent free radical scavenging activity. Detailed studies on chemical composition, isolation of active constituents and pharmacological evaluation are essential to characterize them as biological antioxidants. The present findings of this study support the view that Delphinium Staphisagria seeds are a promising source of potential antioxidant which can be used in treatment of various ailments.