The findings show that Thai schoolchildren interpret the causes of health and sickness using their cultural knowledge and commonsense knowledge as well as school knowledge learned in the classroom. The cultural and commonsense knowledge are remarkedly different from what they are taught. More importantly, when the children employ school knowledge, the explanations are still very much commonsense interpretations. What do these findings imply then? They suggest that despite lengthy training in the classroom, the influence of the culture in which the children are growing up and their everyday experiences play an important role in their learning process. The basis of their understanding of the causes of health and sickness still seems to be in cultural and commonsense knowledge.