The authors investigated the tendency and feature of adverse reaction reports of rabies vaccines for animal use submitted from the 2003 to 2005 fiscal years. The results confirmed that the rabies vaccine was safer than commercial canine combination vaccines given the percentage of adverse reactions that appeared. However, adverse reactions occur frequently in dogs less than one year old and dogs between ten and twelve years old. Adverse reactionsalso tended to occur on the day of the vaccination, and particularly within six hours for serious cases. Moreover, this investigation showed that anaphylaxis accounts for half of all adverse reactions. The results suggest that dogs should be observed carefully on the day after the vaccination, as described in the insert.