Both epidemiological and pharmacoclinical research have been carried out on children suffering from headache. Two epidemiological trials were performed. In the first, 562 migrainous children were questioned about several clinical symptoms that affect child headache suffers, and the incidence of these symptoms was recorded. In the second, we divided 504 nonselected school children into three groups: headache sufferers and nonheadache sufferers with or without family headache history. The same clinical symptoms were studied. Statistical analysis showed that motion sickness, recurrent abdominal pain, sleeping troubles, hyperactivity, cyclic vomiting, dizzines, and limb pain have different incidences in the three groups. These clinical symptoms and family headache history may be considered HR factors and indicate a predisposition to headache in children. The pharmacoclinical study was carried out on 15 migrainous children, five hyperactive and 10 controls. An increased sensitivity of iris adrenergic receptor in both migrainous and hyperactive children was evidenced by measuring phenylephrine-induced mydriasis. The possible etiopathogenetic correlations among headache, hyperactivity, and other HR factors are discussed in accordance with the central theory of headache.