We examined whether a prick test was a valuable method in comparison with an intradermal skin test for predicting an anaphylactoid reaction to intravenous injection of fluorescein solution. Fifteen hundred cases were tested. The number (rate) of positive reactions to the prick test with 10% and 1.0% fluorescein solution was 2 (0.1%) and 0 (0.0%), respectively. In contrast, positive reaction to the intradermal skin tests with 10% and 0.1% fluorescein solution was observed in 686 cases (45.7%) and 13 cases (0.9%), respectively. Fluorescein angiography (FAG) was performed in 1,499 of the 1,500 cases. Adverse reactions such as nausea, cough, cold sweat, urticaria, and shock were noted in 85 cases (5.7%). Typical anaphylactoid shock occurred in one case (0.07%), which was one of the two cases positive to the prick test with 10% fluorescein. In the other positive prick test case, FAG was cancelled because of the high probability of anaphylactoid shock. The results suggest that a prick test with 10% fluorescein solution can markedly cut down the false positive reactions and can be a useful test for the prospective diagnosis of anaphylactoid reactions to intravenous fluorescein administration.