Is Sulfur the culprit?

I take Sulfasalazine, a 5-ASA drug. It is based off of Sulfur. So, unfortunately, it is not caused by it.

My friends that do have a sulfur allergy/reactions from sulfur say it does not manifest symptoms in the gastro tract. They get headaches, and other symptoms. But not in the intestines.

Actually, the Low FODMAP diet helped me with gas and a couple of other symptoms. You might want to check it out.

Taking Butyric Acid supplements also helps me greatly. You should try Sodium Butyrate. I also take L-Glutamine. These really help my flareups.

Yes! The butyrate is what detoxifies the sulfur! I've been taking fiber because fiber is supposed to make butyrate and it seems to be helping me too. So interesting! :o) I was wondering if I should just take straight butyrate supplements instead or if it makes much difference.

There's no sulfa in the oral, PH-based delayed-release-coated mesalamines (asacol, lailda, apriso, pentasa-oral).

However, the oral sulfasalazine contains sulfa and the mesalamine retention enemas (rowasa/salofalk/pentasa enemas) also contain sulfites as preservatives. Some of us have sulfa allergies and those are going to give trouble to those individuals.

There is no absolute right or wrong when you are talking about Ulcerative Colitis and our individual responses to foods. Try avoiding them and see if that helps: might do nothing, might do something, and only you can tell.

Sulfur in the diet is definitely great for most people. Everyone needs it but some of us can't tolerate high sulfur foods in the diet. It made my situation much worse till I figured it out. Not everyone with UC has sulfur issues but there is a decent enough percentage do have high SRB to warrant it's consideration. In my case, cabbage, broccoli, garlic, onions, kale, mustard, beans all these delicious foods that are healthy would cause a lot of pain and bleeding, not to mention the worst of odors. I don't believe addressing SRB to be a one size fits all approach but it helped me quite a bit until I was able to change the microbiome environment enough to be able to reintroduce these foods in moderation.
Intestinal motility that is too rapid unfortunately is supportive of shifting the microbiome toward high SRB.

Sure, always happy to share.
My research led me to altering intestinal motility as a more sufficient means to altering the microbiome. It is already well established science that Sulfate Reducing Bactera(SRB) are more likely to thrive in a rapid motility situation vs say methanogens which are typically higher in slow transit. Taking general probiotics in these cases may not be all that effective in this situation because ultimately, the environment of the microbiome is a large determinant of what will inhabit your intestines. I'll be leaving out a lot of details so I don't create a wall of text here but SRB don't compete well in most situations but their strengths come from rapid reproduction and their ability to use a wide range of energy sources with an emphasis on sulfur allowing them to survive in tougher environments. Rapid reproduction is a big part of how they are able to thrive and outcompete during rapid transit with a lot of washout typical of diarrhea. They don't seem to compete as well in slower transit however due to various factors that may drag me off topic but it caused me to reason that slowing my motility would likely shift me away from SRB.
The items I used are:
Lactobacillus Reuteri which likely directly affects a receptor and is proven to slow motility in the small intestine via the migrating motor complex.
I am also taking raw Cacao powder on the assumption of anandamide increases. I have no solid evidence I am getting significantly more anandamide, however I couldn't find pure anandamide nor a better source at the time of research. I need more data on this. Anandamide affects the CB1 receptor which reduces motility though some may be ok using THC instead.
Lastly, I am using loperamide HCL. A rather well known anti diarrheal medicine. This is my least favorite and something I will be moving away from once I either feel my biome has shifted enough or I find a better replacement. This slows motility in the colon only which is why I felt a combination was necessary as I believe regulating the small intestine to be as vital as the colon.

A few other things I should mention, in terms of rapid transit, my motility was around 12-24 hours. Currently I am in a 24-36 hour range and it has helped quite a bit. I can now eat most of the sulfur bad list foods as long as I don't overdo the onions, garlic or most hot sauces I really like.

I have been avoiding nitric oxide supplements including beet juice which I hope to get back to at some point for the health of it but nitric oxide stimulates the smooth muscle cells and expedites motility. I also take nicotine which it sounds like may have an effect on the amount of water that is sent through via effects on ion transport, especially salt. I didn't learn this until recently but it gave me another reason to like nicotine supplements.
I wouldn't recommend anyone to try this without a full understanding of what they're doing or an appropriate medical opinion as very slow motility can be bad just like very fast motility.