We retrospectively studied use of complementary medicine in children with Attention Deficit Hyperactivity Disorder, epilepsy, and controls. Parents of patients with Attention Deficit Hyperactivity Disorder (n = 120; mean age 11.0 +/- 3.1 years), epilepsy (n = 115; 10.9 +/- 5.5), and healthy children seen in the emergency room during an acute illness (n = 115; 5.0 +/- 4.9) were individually interviewed regarding past and present use of complementary medicine. We found that 34 children with Attention Deficit Hyperactivity Disorder, 37 with epilepsy, and 24 controls had, at some time during their life, received complementary medicine: diet (n = 50), homeopathy (n = 46), acupuncture (n = 23), and biofeedback (n = 9). Current use was significantly less: Attention Deficit Hyperactivity Disorder- 7.5%, epilepsy-14%, and controls-7%. No differences among groups were found for either past use or method of complementary medicine employed. However, the most significant predictor for current use of complementary medicine was past use (OR 3.2, P < 0.001), followed by level of father's education (OR = 1.16, P = 0.01). There was a trend for more children with epilepsy (OR = 1.7) and children from religious families (OR = 1.51) to be currently receiving complementary medicine. In summary, only a small minority of patients with either Attention Deficit Hyperactivity Disorder or epilepsy used complementary medicine as part of their current medical regimen, although during their lifetime a third had received complementary medicine. Complementary medicine was more consistently used in children who had previously received complementary medicine, regardless of their medical diagnosis.