What ingredients do Bernaise sauce and fruit smoothies have in common? I am trying to narrow down the source of a food allergy. I had a really bad reaction recently and that was my second bad reaction in 2 years. In the first instance, it was after drinking a fruit smoothie at Smoothie King with "all natural" ingredients, I may or may not have had one with the turbinado in it. The second time was this past week at a steakhouse where I tried the Bernaise sauce. I'm assuming that they made it in house but it may have very well been from a vendor. 

So, can someone please help me figure out what ingredients those two foods would have in common? Someone suggested that maybe cornstarch was in both of those? Are there any other common ingredients?
Bernaise = butter, egg, vinegar (usually white wine), salt, pepper, and herbs.  It would surprise me if any of those things were in your smoothie. So, based on the information you provided, I would say they have nothing in common. Beyond that, you would have to go the the Smoothie King, and the steak house, and ask for a list of ingredients to see if there is something out of the ordinary in their recipes.  Maybe you should just go see your physician.