Objective To describe trends in clonidine exposures in children under 6. Clonidine has become increasingly popular for management of paediatric behavioural disorders. Clonidine has a narrow therapeutic index, and toxicity can occur with inadvertent double dosing. Clonidine is not recommended for use in children under 6 years. Design and setting A retrospective review of clonidine exposures in children under 6 reported to the New South Wales Poisons Information Centre (NSWPIC, Australia's largest poison centre), 2004-2017. This was compared with community clonidine utilisation using dispensing data from Australian Statistics on Medicines, 2004-2015. Australian trends were compared with clonidine exposure calls to US poison centres, 2006-2016. Main outcome measures Trends in poisonings and dispensing; demographics, dose, exposure type, clonidine source, symptoms, disposition. Results There were 802 clonidine exposures in the NSWPIC database, increasing 4.9% per year, 2004-2017 (95% CI 3.1% to 6.7%, p<0.001), correlated with increased dispensing, r=0.846 (95% CI 0.529 to 0.956, p<0.001). 78.6% were hospitalised and medical toxicologists were consulted in 7.2%, indicating high risk and/or morbidity. Clonidine was prescribed for the patient in at least 27.8%, providing evidence for prescribing outside of recommendations. US data reveals 19 056 clonidine exposures, with 3.7% increase per year, 2006-2016 (95% CI 2.2% to 5.3%, p<0.001). Conclusions Clonidine exposures in children under 6 are increasing, and this trend is not isolated to Australia. Exposures have a high hospital referral rate and high morbidity. Caution should be exercised when prescribing clonidine, and parent/carer education is important for safe storage and increased vigilance when dosing.