For treating parasitic infections and several other uses. Germany seems to use more treatment options than the AMA in the states and often their herb processing is considered to meet higher standard than many countries. In the USA herb processing and selling is not FDA controlled. Artemisinin is an extract of artemisia by the way.
Using herbal medicines can be just as dangerous as any Rx from a doctor's office when it comes to side effects and drug interactions yet often there is no one to tell you this fact. The link above points out uses and side effects of artemisia.