I also took yellow sulphur for app. 3 months early in my treatment. I bought mine from a feed store and put it into gelatine capsules. I can honestly say I feel it did nothing for me but then, again, I was not fighting intestinal parasites, mine are skin parasites.
it is given to horses regularly in Australia in molasses to cover the taste, so it may well have some anti-parasitic action.
I do think it has some antibacterial action for sure as the first Antibiotics were sulphur based.