This invention relates to the use of certain C-10 substituted derivatives
of artemisinin of general formula (I) in the treatment and/or prophylaxis
of diseases caused by infection with a parasite, certain novel C-10
substitued derivatives of artemisinin, processes for their preparation
and pharmaceutical compositions containing such C-10 substituted
derivatives. The compounds are particularly effective in the treatment of
malaria, neosporosis and coccidiosis.