Summary: A study of the episodes of acute respiratory infection (ARI) that occurred in a paediatrician's daughter during infancy, revealed 11 episodes with an average duration of 8.7 days (range: 3-18 days). In nine of the episodes, family members experienced ARI which preceded that of the infant by a mean of four days (range: two-seven days). Relevant factors to this ARI experience included family size, number of siblings at school and household irritants. Most of the ARI episodes in the infant required only liberal intake of oral fluids, breast feeding and nasal toiletting.