Objective:To evaluate the cardiac activity and hepatoprotection of Crataegus sinaica (C.sinaica).Methods:All the isolated compounds were isolated by open-column liquid chromatography(CC) using sephadex LH-20 as stationary phase.Elution of the column was performed with EtOH or MeOH.The phytochemical investigation of the young stem of C.sinaica for the first time together with the leaves and flowers lead to the isolation and identification of quercetin,hyperoside,vitexin-2“-0-rhamnoside,epicatechin,procyanidin B2 and procyanidins CI.Results:Rats treated with the low and high dose of C.sinaica leaves with flowers extract showed 15%and 17%reduction in the heart rate,and reduction in the STsegment by 107%and 57%;respectively.The T-amplitude was decreased by 59%of the high dose extract.On the other hand,the young steins and leaves with flowers extracts of C.sinaica on primary culture of rat hepatocytes monolayer indicated a hepatoprotection for the total extract,ethyl acetate,butanol,and chlor of orm fractions at 100μg/mL,75μg/mL,50μg/mL,and 25μg/mL; respectively.Conclusions:The results of these chemical and biological studies suggest the use of C.sinaica growing in Egypt as a preventive drug against cardiovascular and hepatic diseases. The chemical studies suggest the use of woody young stems as a newly investigated bioactive organ.The extraction of unsaturated fatty acids from the seeds of the plant would serve as a good health and nutritive product. Objective: To evaluate the cardiac activity and hepatoprotection of Crataegus sinaica (C.sinaica). Methods: All the isolated compounds were isolated by open-column liquid chromatography (CC) using sephadex LH-20 as stationary phase. with EtOH or MeOH. The phytochemical investigation of the young stem of C.sinaica for the first time together with the leaves and flowers lead to the isolation of identification of quercetin, hyperoside, vitexin-2 ”- 0-rhamnoside, epicatechin, procyanidin B2 and procyanidins CI. Results: Rats treated with the low and high dose of C.sinaica leaves with flowers extract showed 15% and 17% reduction in the heart rate, and reduction in the ST segment by 107% and 57%; respectively. T-amplitude was decreased by 59% of the high dose extract. On the other hand, the young steins and leaves with flowers extracts of C.sinaica on primary culture of rat hepatocytes monolayer indicated a hepatoprotection for the total extract, ethyl acetate, butanol , and ch lor of orm fractions at 100 μg / mL, 75 μg / mL, 50 μg / mL, and 25 μg / mL; respectively. Conclusions: The results of these chemical and biological studies suggest the use of C.sinaica growing in Egypt as a preventive drug for cardiovascular The chemical studies suggest the use of woody young stems as a newly investigated bioactive organ. The extraction of unsaturated fatty acids from the seeds of the plant would serve as a good health and nutritive product.