I'm plotting the output of enrichGO from the clusterProfiler package. The font size is so small it is illegible (even in the Vignette here: https://bioconductor.org/packages/release/bioc/vignettes/topGO/inst/doc/topGO.pdf). 

Is there a way to increase the font and node size?

Many thanks,

Stephen  

You can try changing graphical parameter function using 

par(cex = 0.5)

The size of the font is inversely proportional to the cex value in this case.