Gblocks is a program written in ANSI C language that eliminates poorly aligned positions and divergent regions of an alignment of DNA or protein sequences. These positions may not be homologous or may have been saturated by multiple substitutions and it is convenient to eliminate them prior to phylogenetic analysis. The use of a program such as Gblocks reduces the necessity of manually editing multiple alignments, makes the automation of phylogenetic analysis of large data sets feasible and, finally, facilitates the reproduction of the alignments and subsequent phylogenetic analysis by other researchers. Gblocks is very fast in processing alignments and it is therefore highly suitable for large-scale phylogenetic analyses. This just repackages the binaries provided from upstream.