An open prospective study using i.v. methylprednisolone in children with juvenile chronic arthritis (JCA) who had had a systemic exacerbation of disease is described. Eighteen children aged from 3 to 14 yr and 9 months (mean 9.7 yr) were treated. Ten patients (55%) had a loss of all systemic features 1 month after the pulse, and eight (45%) had a reduction in the active joint count. At this time, five of the patients on oral prednisolone had achieved a reduction in dosage. Also at 1 month, a reduction in erythrocyte sedimentation rate was observed in 11 patients (61%) and of C-reactive protein in 11 of 16 (72%). Altogether, 13 patients (72%) had a good response, while a further three (16%) went into remission. Our conclusions are that pulse methylprednisolone provides good short-term benefit in patients with systemic-onset JCA; no serious side-effects were noted. Further long-term studies are warranted.