CJ-50001 is a recombinant granulocyte-colony stimulating factor (rG-CSF) synthesized by recombinant DNA technology using E. coli as an expression system. The general pharmacological properties of CJ50001 were evaluated in mice, rats, dogs and isolated guinea pig ileum. The doses are 100, 300 and 1,000 ㎍/㎏, i.v. for mice and rats, 1, 10 and 100 ㎍/㎏, i.v. for dogs and 1 and 10㎍/ml for isolated guinea pig ileum. Intravenous administration of CJ-50001 at this dose range did not affect general behavior, central nervous system, smooth muscles, gastrointestinal system, cardiovascular and respiratory system and water and electrolytes excretion. In summary, CJ-50001 had no harmful pharmacological effect in these studies even up to the 200-fold expected clinical dose, 250 ㎍/man.