Both can potentially inflame the liver, however you should be monitored closely while on each med for liver issues. I'm on both Remicade and 6MP. Recently my liver enzymes came back elevated. Dropped down to 75mg 6MP and they are normal now. As long as the liver tests are normal, neither should really be bothering the liver.
"What can't be changed must be endured" - unknown
DX with distal Crohn's colitis Oct 2007, predominantly in rectum
Colozal and Canasa for 2+ years - developed an intolerance
6MP - elevated LFTs after 100mg, no effect after 9 months
Currently: Remicade (Nov '09), and Paleo Diet. Not quite remission, but so much better!