In this randomized clinical trial before and after study we will assess the effect of L-citrulline malate on brachial index in patients with coronary heart disease based on their smoking history. Twenty patients with coronary heart disease with no history of diabetes or other chronic diseases and with no history of myocardial infarction in the last 6 months will participate in our trial.A written well-versed permission was attained from all patients. We will measure the brachial index tow times once before giving L-Citrulline malate and the other time after 2 weeks giving it.Patients receiving L-Citrulline malate as a 1 gram dry powder agent twice a day, that should in use with 250 mg dilute water .The patients will followed after 2 weeks by measuring brachial index which is our primary outcome measurement in this trial.We assumed that the brachial index in both smoker and non-smoker group of patients with coronary heart disease would change to normal or close to normal after giving 1 gram L-citrulline malate twice a day for 2 weeks.