<<Disclaimer: Verify this information before applying it to your situation.>> Hi All, The mustard I believe I reacted to was Coleman's dry mustard. I thought it was pure, certainly has no vinegar. I was under the impression that this product - a good old British tradition - contained nothing but mustard. If Coleman's isn't pure mustard, what is ? I'll read labels at the store to see what they say. If it appears to be gluten free I'll try it again. I would love to be wrong on this one. The horseradish I use IS pure dried ground root. No vinegar, no additives. Thanks for the input. Jessie on Salt Spring Island BC