This invention comprises compositions containing dihydroartemisinin- and dihydroartemisitene-dimers with activity as anticancer or anticancer metastasis agents and anti-protozal, including anti-malarial and anti-leishmanial properties. This invention also describes methods of preparation of these compositions and methods of use of such compositions for the treatment of cancer or prevention of cancer metastasis, and protozoal infections, including malaria, or leishmaniasis. The compounds of this invention represent a potential new class of anti-tumor or anti-metastasis agents, one that has shown promising activity against solid tumors.