This analysis, from the International Study of Asthma and Allergies in Childhood (ISAAC), involved more than 200,000 six- and seven-year-old children from 73 centers in 31 countries. The children’s parents or guardians completed written questionnaires about current symptoms of asthma, rhinitis (hayfever), and eczema, and about several risk factors, including use of paracetamol for fever in the child’s first year of life and frequency of paracetamol use in the past 12 months.