The safety of sympathomimetic decongestants (SMDs) in patients with hypertension remains controversial. Little experimental evidence exists for making proper recommendations regarding their use in hypertensive subjects. In order to determine the correct role of SMDs in such patients, physicians will need criteria with which to assess new data and reevaluate the existing literature. Using standardized methodologic criteria to judge clinical trials, we critically appraised the published evidence of the effects of SMDs on blood pressure control in hypertensive patients. A search of the English literature from 1966 to 1984 revealed 12 prospective clinical studies out of 37 articles that specifically addressed the potential adverse pressor effect of SMDs. Of these, only one study evaluated hypertensive patients in a double-blind randomized fashion. Despite few threats to generalizability, the results of that investigation suggest that intranasal phenylephrine is safe in patients with controlled hypertension. The effects of phenylpropanolamine and pseudoephedrine in hypertensive patients are unclear since only small numbers of unrepresentative normotensive subjects have been studied; thus, the evidence to support the widespread belief that SMDs are unsafe in hypertensive patients is weak and circumstantial. Recommendations for treatment and methods to improve future study designs are suggested.