Two experiments evaluated the frequently reported claim that young children consider illness a form of punishment for misdeeds, or immanent justice. Most preschoolers in these experiments rejected the possibility of immanent justice, preferring instead the idea that illness results from contact with contaminants such as germs. Of the children who appeared to believe in immanent justice (e.g., by assenting that eating a stolen apple can make someone sick), many had been making assumptions about material contamination (e.g., the original owner was sick and contaminated the apple). Overall, children were more likely than adults to consider mild forms of contamination harmful. The results of these experiments are consistent with recent demonstrations of sophistication in early reasoning about biological phenomena.