Antibiotics isn't the way to treat ulcerative colitis
If you wipe out your bowel flora with Antibiotics you may temporarily relieve the colitis but you will do nothing to improve your immune system and inflammatory reactions.
Likewise with steroids and NSAIDs
Read through this forum and you'll get a better idea how you could treat it without drugs.
I know what the best thing for me is but there are several approaches. Those that work all involve correcting diet, then usually adding vitamin and mineral supplements to correct deficiencies which are worsened by the colitis and using anti-inflammatory foods and herbs.
Addressing mercury toxicity is also important. I may have done this by the amount of Iodide and selenium I took.
I still have Amalgams to get rid of but possibly mercury removal from the bowel was a big factor in my case.
I beleive if the bowel wall has enough Iodide then it is protected from mercury and bacterial invasion.
Poor adrenal function could also be a factor which also could be due to mercury among other things like stress