Purpose: To see if the use of sympathomimetic amines, which have been shown to treat cases of hives, can help prevent cyclical urticaria and anaphylaxis associated with the late luteal phase that was resistant to standard treatment. Materials and Methods: Treatment with low dose dextroamphetamine sulfate to gain relief of symptoms was given to one young woman whose urticaria only occurred premenstrually, but was also associated with life threatening anaphylaxis. Patient 2 had chronic daily urticaria which was exacerbated premenstrually. Results: Both patients showed prompt 100% improvement in the urticaria. Patient 2 after 20 years of therapy ran out of medication for one month. Her severe urticaria quickly returned only to dissipate when dextroamphetamine sulfate was restarted. Conclusion: Use of dextroamphetamine sulfate was successful in treating the anaphylaxis and extensive luteal phase hives in patient 1 as well as treating chronic hives with a premenstrual exacerbation in patient 2. These cases are both consistent with the proposed mechanism of the sympathetic neural hyperalgesia edema syndrome, i.e., increased cellular permeability related to sympathetic nervous system hypofunction of specific permeability defects of certain tissues. In these cases, the hypothesis is that the increased permeability manifests as leakage from the vesicles that contain the histamines.