After the oral administration of the COX 2 inhibitor rofecoxib (Vioxx) as part of an oral provocation test, a 64-year-old woman developed acute anterograde and retrograde amnesia which lasted for several hours. The patient did not show symptoms of anaphylaxis. Neurological examination did not reveal focal symptoms or an epileptic seizure. Diffusion-weighted magnetic resonance imaging only showed a small region of increased signal intensity in the left hippocampus. The patient thus had no anaphylactic drug reaction, but a transient global amnesia (TGA) or amnestic episode. TGA is an acute, reversible, cerebral dysfunctional state which lasts from 1 h up to maximally 24 h and which is associated with anterograde and retrograde amnesia. While about half of the cases appear to occur spontaneously, other cases are preceded by physically or emotionally stressful events. In our patient it may have been the emotional distress caused by the oral provocation testing that has triggered the TGA. When TGA occurs during oral challenge of drugs, we recommend repeating the oral challenge of the tested drug.