OBJECTIVE To investigate whether the lack of knowledge of toxic agents in households is a risk factor for individual unintentional childhood poisoning. METHODS The case group (n = 25) was composed of caregivers of children under 60 months of age who underwent accidental oral poisoning and were treated at two reference hospitals in Porto Alegre, southern Brazil, and recorded in the Toxicology Information Center database. The control group (n = 25) was composed of caregivers of children matched for sex, age, and presence in their homes of the same toxic agents found in the case group, who sought emergency medical care at the same hospitals, but for other reasons. A structured questionnaire was administered to verify the following questions: sociodemographic data, clinical history, behavioral antecedents of caregivers, storage of toxic agents, history of previous poisoning accidents. RESULTS The children's mean age was 31.8 months (±0.97) and mean height was 93 cm (±11). Families, in both groups, were aware of the toxic action of agents available in their homes; however, caregivers in the control group were twice as likely to have such knowledge compared to the case group. Distraction was 15 times more likely to occur among caregivers of children who underwent poisoning compared to the control group. Storage of toxic agents below 150 cm was approximately 17 times more likely to occur in the group of children who underwent poisoning compared to children in the control group. CONCLUSIONS Lack of knowledge of the toxic action of agents stored in households is not a risk factor for childhood poisoning. The attributable risks described in this study indicated that the elimination of other factors, such as distraction and storage below 150 cm, would lead to the prevention of 13 and 19% of poisonings in childhood, respectively.