Objective: To investigate the contents of home medicine chests and their relationship with self-medication in children and adolescents in the towns of Limeira and Piracicaba, SP, Brazil. Methods: This is a descriptive population study based on ahome survey of a simple random sample from both towns, comprising 705 households from census sectors selected by means of cluster sampling. Inclusion criteria: age ≤ 18 years; an obligatory interview with at least one guardian; inventory of medicines kept at home; and having taken at least one medication during the 15 days prior to the interview. The participants were split into two groups based on medication: self-medication (lay advice) and medical prescription. Tests of linear association were performed, in addition to a descriptive analysis of the variables and multiple logistic regression. Results: A total of 3,619 medicines were found (mean = 5.1/ household; 79.6% were pharmaceutical preparations). The rooms most commonly used to store medications were bedrooms (47.5%), kitchens (29.9%), and bathrooms (14.6%); 76.5% were in cardboard boxes and within easy reach of 142 children aged ≤ 6 years. Taking the pharmaceutical preparations in isolation (n = 2,891), the most common were analgesics/antipyretics (26.8%) and systemic antibiotics (15.3%), and the self-medication group had significantly larger stocks of these medications (p < 0.01). Storing medications in the bathroom (odds ratios = 1.59) and legal guardians with ≤ 4 years of primary education (odds ratios = 2.40) indicated greater risk of self-medication. Conclusions: Keeping medicines at home is a common practice, and it is important to implement campaigns to encourage rational use, reduced waste and safe storage of medicines. Copyright © 2008 by Sociedade Brasileira de Pediatria.845416422World Health Organization. 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