Propranolol is a ß-blocking drug with therapeutic utility as an antianginal and antiarrhythmic agent and an antihypertensive and antimigraine agent. Nonselective ß-adrenergic blocking drugs, numbering about 15 including propranolol, competitively block response to ß- and ß-adrenergic stimulation, which results in decreases in heart rate, myocardial contractility, blood pressure, and myocardial oxygen demand. In animal studies, propranolol had little adverse developmental effect. Authors of published studies on the developmental effects in humans caused by propranolol reported few adverse findings. A solitary study reported a case of tracheoesophageal fistula and intrauterine growth retardation in an infant whose mother was treated with 80 mg/day of the drug throughout the first trimester. Propranolol is a hydrophobic molecule with average size in comparison to the other human developmental toxicants. It can participate in hydrogen bonding, both as acceptor and donor.