A consensus meeting held under the auspices of the European School of Oncology concluded that the use of granulocyte growth factors is definitely indicated, or acceptable given existing evidence, in the following circumstances: to alleviate congenital neutropenia; in the mobilisation of peripheral blood progenitor cells for autotransfusion; to encourage engraftment following bone marrow transplantation and in cases of failed engraftment; to support continuation of ganciclovir anti-CMV therapy in certain patients with AIDS, where the switch to foscarnet is contraindicated or where toxicity to foscarnet develops. It was also agreed that there is an overwhelming need for carefully controlled clinical trials in a wide range of indications in which growth factor use may improve outcome. In the majority of tumours, the possible benefit of dose optimisation and intensification, and therefore the role of growth factors in support of such measures has still to be defined. Extramedullary toxicities may in these instances become dose limiting.