When macrophages were cultured with lactoferrin, cytokines such as tumor necrosis factor (TNF‐α), interleukin 8 (IL‐8) and nitric oxide (NO) were secreted. Secretion of TNF‐α peaked at 6 h of incubation in the presence of lactoferrin and then declined. About 80% of the maximum secretion of IL‐8 was observed at 6 h of incubation. The concentration of IL‐8 in the culture medium remained almost constant between 24‐72 h. In contrast, no siginificant effect on NO secretion was observed at 6 h, but a significant effect was observed at 24 h and secretion gradually increased between 24‐72 h. The effects of lactoferrin on the secretion of TNF‐α, IL‐8 and NO were dose‐dependent and lactoferrin had a significant effect on secretion at concentrations greater than 10 mg/ml. The use of reverse transcription‐polymerase chain reaction (RT‐PCR) showed that the results obtained were consistant with the cytokine secretion results. It is concluded that lactoferrin activates macrophages which result in the secretion of TNF‐α, IL‐8 and NO.