OBJECTIVE: Colchicine is an alkaloid that is used to alleviate acute gout and to prevent acute attacks of familial Mediterranean fever (FMF). However, it is not beneficial when given during the occurrence of an acute episode of FMF. It is believed that colchicine exerts its anti-inflammatory effect through direct interaction with microtubules. We aim to study the molecular basis of colchicine action by analysing the effect of this drug on global gene expression of HUVEC (human umbilical vein endothelial cell line) cells. METHODS: HUVEC cells were exposed to various concentrations of colchicine and were harvested at different time points. Ribonucleic acid was extracted, amplified, reverse transcribed and hybridized to complementary deoxyribonucleic acid microarrrays containing more than 40,000 probes to human expressed sequence tags. This approach enabled us to have a global look at the transcriptional response induced by colchicine treatment. RESULTS: Colchicine changed the expression of many genes in HUVEC cells following exposure to a concentration of 100 ng/ml or higher. Following short exposure (30 or 120 min), colchicine affected genes known to be involved in the cell cycle and its regulation. However, change in expression of genes involved in neutrophil migration or other inflammatory processes were observed mainly after 12 to 24 h. CONCLUSIONS: The anti-inflammatory effect of colchicine may be mediated not only through direct interaction with microtubules but also through changes at the transcriptional level. This latter effect apparently requires a higher concentration and a longer time to occur. This can explain the observation that colchicine does not have an immediate effect when given during an acute attack of FMF.