Lush Aromaco Deordant

Got this as a sample when I had purchased some bath bombs. When I first got the sample I really liked it and it worked well, but once I purchased it I'm not to sure how I feel about it. I mean I still like how it works, the smell isn't that bad but its a whole lot stronger in the bigger pieces. My only problem with it is I cannot use it every day, if I do my underarms become red. Only thing I can see is that I'm allergic to Sulfa products, so maybe this has a strong content of it?! Not to sure, other then that it works great.