Two types of recombinant human granulocyte colony-stimulating factor (rhG-CSF) are available, and equally used for mitigation of neutropenia. One is a glycosylated natural product from mammalian cells, and the other a non-glycosylated form from Escherichia coli. Though only minimal adverse effects have been reported for both, we treated two patients with rhG-CSF-induced systemic eruption. Based on these patients, the following should be noted: 1) drug eruption may occur in both types of rhG-CSF without detectable antibodies, 2) intradermal test is useful for determination of the causal drug, and 3) if one rhG-CSF product causes eruption, the alternative one may possibly be safe and effective.