The rapper has passed on 12 dates on this side of The Pond, leaving promoters with a tough choice: plough ahead with 50 Cent and the tour's backing roster, or to pull the plug altogether.
An Interscope spokesman told reporters: "Eminem is currently being treated for exhaustion, complicated by other medical issues".
The European dates, including shows in the UK and Ireland, are due to begin on September 1st in Hamburg.
The Sun has reported that Eminem is to give up on music completely, leaving his career to concentrate on bringing up his daughter Hailie.
It's estimated that the rapper, 32, will lose £10m after cancelling European dates. 330,000 people were expected to attend UK and Ireland shows alone.