As widely recognized, it is extremely difficult to confirm that individual animals have been successfully treated using traditional blowdart treatment methods, particularly when the animal groups are large and crowded, or when the animals' external morphologies closely resemble each other. Misidentification has therefore become the primary cause of double treatment or lack of treatment of single individuals. To resolve this problem, we ran a two-year experiment in a modified traditional blowdart treatment at the Animal Medical Center of Taipei Zoo. This experiment focused mainly on developing the auto-marking blowdart as a substitute for the conventional blowdart, and applying the auto-marking system to indicate completion of treatment. Experimental results demonstrate that the auto-marking blowdart can be applied successfully and efficiently in wildlife group medical treatments.