The key thing is the function bquote(). E.g. > N <- 5 > xxx <- bquote(bold("Figure"~.(N)~"Plot"~C[max]~"versus CrCl")) > plot(1:10,main=xxx) (Not sure about the ``bold'' business, but R doesn't object.) Or to take a simpler and clearer example: > N <- 5 > plot(1:10,main=bquote("Figure"~.(N)) cheers, Rolf Turner rolf at math.unb.ca