Certain animals have represented a danger to humans in terms of a predation and pathogen threat over our evolutionary history. It is therefore adaptive for people to respond to a potential threat faster than to harmless events. Using simple choice tasks, the reaction time of children to predators, disease carriers and aposematically coloured animals were investigated. Children reacted the fastest to predators, followed by disease carriers and finally aposematically coloured animals. Furthermore, children manifested the highest accuracy when distinguishing predators from non-predators, followed by disease carriers and harmless animals, with the most errors occurring when identifying the aposematically coloured from non-aposematically coloured animals. Importantly, children more vulnerable to infectious diseases responded to disease carriers faster than healthier children. These results suggest that children are skilled in distinguishing potential danger from non-danger and that the behavioural immune system influences reaction times in visual contact with the pathogen threat.