The present invention relates to compounds with an increased in vivo biological activity, and especially an increased pharmaceutical activity, such as an anti-nematodal or antifungal activity, an immunosuppresive activity, a metabolism influencing activity and/or an anti-cancer activity. Specifically, the present invention relates to compound comprising an artemisinin derivative according to the general formula (I) covalently linked at the 1 or the 2 position to a compound with a biological activity thereby increasing the biological activity of said compound or a pharmaceutically acceptable salt thereof.