The naphthoquinone contents of greenhouse cultivated Australian and South-African Drosera species (D. binata, D. binata var. dichotoma and D. capensis) have been investigated with regard to the plant organ, propagation method and plant development stage. Comparative analyses have been carried out on native populations of D. rotundifolia L., European species of pharmaceutical interest. D. binata and mostly D. binata var. dichotoma represent good natural sources of plumbagin, the only quinone occurring in these Australian species, otherwise D. capensis must be regarded as an interesting natural source of 7-methyljuglone, the only naphthoquinone ubiquitously occurring in all the plant organs.