AIM: To determine the period prevalence and nature of complementary and alternative medicine (CAM) use among paediatric emergency department (ED) patients and the perceptions of CAM among the CAM administrators. METHODS: A survey was undertaken in four Victorian EDs (January to September 2013). A convenience sample of parents/carers accompanying paediatric patients completed a self-administered questionnaire. The main outcome measures were CAM use and perceptions of CAM. RESULTS: The parents/carers of 883 patients participated. Three hundred eighty-eight (43.9 , 95 confidence interval (CI) 40.6-47.3) and 53 (6.0 , 95 CI 4.6-7.8) patients had taken a CAM within the previous 12 months and on the day of presentation, respectively. There were no gender differences between CAM users and non-users (P = 0.83). The use of CAM was significantly more common among older patients (P <0.001), those with European ethnicity (P = 0.046) and among those with chronic disease (P <0.01). Fish oil, garlic, chamomile and acidophilus were the most commonly used CAM. Only 4.4 of CAM use was reported to the ED doctor. There were reports of potentially dangerous CAM use (St John s wort, ginseng). Parents/carers who had administered CAM were more likely to report that CAMs are safe, drug free and could prevent illness (P <0.01). In addition, a number of this group reported that CAMs are more effective than prescription medicines and safe when taken with prescription medicines. CONCLUSION: CAM use is common among paediatric ED patients although rarely reported to the ED doctor. Parents/carers who administer CAM have differing perceptions of CAM safety from those who do not.