The authors present a spectrum of clinical presentations of transient visual loss/aberrations and show that these occurrences were attributable to ingestion of significant amounts of licorice. A case series of five patients was seen at Geisinger Medical Center between October 1986 and May 1996. Details of patient presentation, treatment, and outcome are discussed. The literature on the effects of licorice derivatives on vascular smooth muscle function is reviewed. Of the five patients, two had documented visual loss by visual acuity testing and visual fields. All patients reported a recent ingestion of significant amounts of licorice (1/4-2 lbs.). All patients had resolution of their visual symptoms; the aid of hyperbaric oxygen was required for one patient. Thorough review of the literature shows recent in vitro and in vivo evidence of glycyrrhetinic acid (the active component of licorice) and carbenoxolone (the hemisuccinate derivative of glycyrrhetinic acid) directly and indirectly enhancing vasoconstrictor action in vascular smooth muscle. It is believed that licorice derivatives can cause retinal or occipital vasospasm, giving rise to transient monocular or binocular visual loss/aberrations. This has not been described before in the literature. It is important to ask about licorice ingestion with patients who present with these visual symptoms.