This study examined the language used by mothers to talk about acute and chronic illness while engaged in a joint book-reading of a story where the main character had a cold. Thirty-four toddlers and their mothers participated in the study. Some of the mothers had a chronic illness, and some of the families or the children had had an acute illness in the past week. Chronically ill mothers used more sick-type words and phrases, possibly reflecting a desire to have their children understand more about living with a chronic illness. When there had been a sickness either in the family or in the child in the past week, mothers used more health-type words and phrases. When children had been sick, mothers were more likely to refer to their illnesses, suggesting that mothers used both experience and social interaction to teach about abstract concepts, such as sickness. (Contains 1 note and 5 tables.)