This invention comprises compositions containing dihydroartemisinin- anddihydroartemisitene- dimers with activity as anticancer or anticancermetastasis agents and anti-protozal, including anti-malarial and anti-leishmanial properties. This invention also describes methods of preparationof these compositions and methods of use of such compositions for thetreatment of cancer or prevention of cancer metastasis, and protozoalinfections, including malaria, or leishmaniasis. The compounds of thisinvention represent a potential new class of anti-tumor or anti-metastasisagents, one that has shown promising activity against solid tumors.