The efficacy and safety of Genotropin (recombinant somatropin, KabiVitrum AB, Sweden) was analysed in 199 children with hGH deficiency, comprising a combined series of four current multicentre trials. Stimulation of linear growth from pretreatment height velocities of 3-4 cm/year to about 10 cm/year was observed after 6 and 9 months of treatment. Statistical analysis revealed significantly greater height velocities (by 2-3 cm/year) when the weekly dose of the hormone was given in 6-7 injections rather than in 3 injections. Immunogenicity seems to be very low, with only about 2% of the children having detectable antibodies during treatment.