Can I take ibuprofen while on asacol (mesalamine) hd? I am not allergic to either one.

Yes. No significant interactions have been reported between Asacol hd & ibuprofen. Avoid using another salicylate (aspirin, peptobismol) in place of Ibuprofen (could lead to salicylate toxicity). Do not take antacids, acid blockers like Zantac (ranitidine) family or Prilosec family at same time as Asacol as they may decrease its effectiveness.
May affect kidneys. Both the medications are known to adversely effect kidney function in some individuals and taking them together may have additive toxic effects on the kidneys. However you may be able to tolerate low doses of Ibuprofen for a short period if your kidney function is normal prior to receiving these drugs. Ibuprofen and other NSAID medications can also irritate the GI tract and rarely cause bleeding.