Granulocyte colony-stimulating factor (G-CSF) is widely used following myeloablative chemotherapy (high-dose therapy; HDT) and peripheral blood progenitor cell rescue (PBPCR) to reduce neutrophil engraftment time. The dose and duration required to gain maximum clinical and economic benefit has not been fully investigated. This double blind placebo-controlled randomised trial was performed to determine whether short course low-dose or standard-dose Lenograstim (L) would influence recovery of haematopoiesis following HDT and PBPCR. Sixty-one patients were randomised between May 1999 and November 2004, to receive standard-dose lenograstim (263 microg/d), low-dose lenograstim (105 microg/d) or placebo injections. These commenced on day +5 following PBPCR and continued until neutrophil engraftment [absolute neutrophil count (ANC)] > or = 0.5 x 10(9)/l. Patients received standard supportive care until haemopoietic recovery. Both standard- and low-dose lenograstim resulted in a significantly shorter median time to neutrophil recovery (ANC > or = 0.1 x 10(9)/l:10.0 vs. 11.0 d, P = 0.025; ANC > or = 0.5 x 10(9)/l:11.0 vs. 14.0 d, P = 0.0002) compared with placebo. There was no significant difference in blood product support, antibiotic usage, documented infection, overall survival or relapse-free survival between the groups. Short course low-dose lenograstim is as effective as standard-dose in reducing neutrophil engraftment time following HDT and PBPCR.