In order to determine the optimum irradiation condition to produce 123I for nuclear medical use, excitation curves and thick-target yield curves were measured by means of stacked foil technique for alpha and 3He reactions producing 123Xe, 123I, 125Xe and 130I, both from natural tellurium. The 123Xe yields from natural tellurium are too low for routine production. However, by bombarding 76.5% isotopically enriched 123Te target with 30MeV 3He particles, 724 micronCi/micronAh of 123I would be obtained, whereas the level of 125I contaminat would be about 0.14%. 130Te contaminant in enriched 123Te target produces 130I alpha and 3He bombardment, although it has not been reported in the past. The 130I contaminant can be easily eliminated.