I was in the area last week and ate at a local restaurant and got sick later in the evening throwing up my dinner. This happened 2 years ago at a different restaurant and in 2007 on the east coast of Florida. The only common denominator is salad or lettuce on a fish sandwich. I have never had the problem at home or on other vacations. I eat shell fish all the time so I know I'm not allergic. Anyone have any suggestions about what is making me sick?