Chemical systematics sets out to interpret the phylogenetic implications of the occurrence and distribution of secondary metabolites. In this review, a number of the major contributions from the 1960's and 1970's are identified and re-assessed in the light of recent evidence gained from DNA studies. It is shown that for the most part conclusions drawn on the basis of secondary metabolite distribution have been confirmed by the new techniques and it is concluded that chemical systematics can continue to provide useful insights into plant phylogeny.