Mesalamine
"I have been taking 4 x Pentasa 500mg twice daily since I was diagnosed with Crohn's in June this year.  I haven't noticed any side effects but my stomach cramping, bloating, gas and just general pain has dramatically decreased so I think it is helping!  Yay.  My specialist has advised that if my symptoms don't totally subside on this medication I've to try a steroid so hopefully it continues to work for me.  Thankfully I'm in Scotland as well so I don't need to pay for the prescription."