To the Editor: The article on “The Carcinoid Flush” by Frölich et al. in the November 9, 1978, issue of the Journal suggests that the clinical signs may be mediated, either directly or indirectly, by pentagastrin. Case 1 had a foregut carcinoid — of gastric origin. Did hyperhistaminemia change during the infusion of pentagastrin and somatostatin? Were prostaglandins or prostaglandin metabolites measured in any of the patients? Were either of the other two carcinoids of foregut origin? What were the silver staining characteristics? If there is an intermediary between pentagastrin (and gastrin) and the carcinoid flush, one wonders if histamine.