Now that PGs (prostaglandins) are becoming more available for the induction of labor and the termination of pregnancy, it is not surprising that some adverse effects to these very potent substances are occurring, especially in patients with preexisting disease. The report by Dr. Roberts and his colleagues (August 26, p. 425) of acrocyanosis during PGF2alpha infusion, probably due to venoconstriction, highlights the problem. The effects of PGF2alpha aerosol on the bronchus have been described, but it is not generally recognized that most patients receiving this drug intravenously develop bronchoconstriction. This is not important in subjects without chest disease, but in patients with a history of asthma it could be most unfortunate. Indeed, the 1st patient to develop asthma owing to PGF2alpha infusion has already been described. In an unpublished series of 11 subjects (8 female, 3 male) investigated in this laboratory, 9 had significant bronchoconstriction, measured by the interruptor method or by body plethysmography, which was proportional to the dose infused (up to 200 mcg/minute). There are clearly some conditions in which PG infusion would be undesirable, and these include those diseases characterized by airways narrowing, in particular bronchial asthma.