Purpose: Children are vulnerable to suffer negative outcomes due to medication (NOM), social media (SM) can be a non-interventional tool to gather safety data. The aim of this study is to assess paediatric Adverse Events (AE) or suspected Adverse Drug Reaction (ADR) detected in SM. Secondary objectives are the assessment of NOM, Drug Related Problems (DRP) and Medication Errors (ME). Methods: Observational, ambispective study assessing NOM in Public Parenting Forums (PPF) using data mining software. Entries that mentioned a medicine administered to children were analyzed and, if NOMs were detected, DRP, ME and AE were categorized. ME and ADR seriousness were assessed. ADR causality according Liverpool Causality Assessment (LCAT) and prevalence compared with those reported in Summary of Product Characteristics (SmPC) of each product. Results: Two forums (mumsnet.uk; socpetit.cat 2733 (81%)) were analyzed. Of 3375 entries, 635 contained a NOM and a DRP, 214 in English, 6 in Spanish and 217 in Catalan. 161 ADR were detected, including Serious AEs (SAEs), unknown, rare or very rare ADR. 29(16%) were not reported in SmPC. 95 ME were found, caused parents or caregivers (40; 42%) and healthcare professionals (HCP) (55; 58%). Severity ranged from no harm up to harm required intervention. Conclusion: ADR were found in PPF, including SAEs and ADR with low or unknown prevalence and suspect ADRs not included in the SmPC. ME that reached children were also found. As consequence, despite that the overall number of entries is not high, forums are a source of valuable pharmacovigilance information.