Despite its small stature, short life-cycle and highly reduced genome, Arabidopsis thaliana has a complement of secondary metabolites that is every bit as numerous and diverse as those of other plant taxa. The list of secondary metabolites isolated from this model species has expanded more than five-fold in the past ten years, and many more substances are likely to be added in the near future. Among the classes of compounds recently discovered are coumarins, benzenoids and terpenoids. Many A. thaliana secondary metabolites appear to have internal roles within the plant instead of (or in addition to) mediating ecological interactions.