I have been off and on having a glass or two of wine and haven't noticed any difference.  My naturopath suggested 'minimal' alcohol, along with avoiding coffee, citrus fruits, and the usual IBS diet changes.  Based on my own experimenting the drink helped me relax, focus less on discomfort and, if anything, helps with looser stools.  I think this can be an irritant for some people and dehydrating if you don't watch your fluids and fruits/veggies. So, 'minimal' or 'moderation' seems like a good plan.  I'm open to hearing if others have more specific information, though.