I use salofalk enemas which are also 5ASA retention enemas. Yes, they can do that...my theory is that blood pools in the colon and is absorbed by the stool. If the colon is starting to heal, the stool and blood will stay in there a bit longer and start to turn darker.
How long have you been on them?
It's all a matter of perspective!
I want you to take ENTERRIC coated Omega 3 fish oil pills to fix your colitis. This will heal the lesions. 3000 mg every 4 hours for a few days or as needed. You will find the enterric coated opens up after the stomach and coats the silica and the walls soothing any pain. You can find the product at certain stores like vitamin shoppe. It must be enterric otherwise it will not do the trick