The plant, Ammi visnaga Lam, known in Arabic as "Khella," grows wild in Arabia, Egypt and Eastern Mediterranean countries.1Of the three crystalline compounds which have been isolated from the fruit of the plant,2visammin (also called khellin) has been claimed to have the greatest biologic activity.3The pharmacology of this compound has been actively investigated4and has recently been summarized.1Early investigators5have demonstrated the ability of visammin to relax smooth muscle in various organs in situ and in isolated structures such as the ureter. Visammin has been found to be a powerful coronary vasodilator in animals, causing definite increase in coronary blood flow without demonstrable ill effect on the myocardium. It is further characterized by the absence of development of tolerance, by a wide margin of therapeutic safety and by prolonged activity, since its gradual disappearance from blood and tissues results in