<<Disclaimer: Verify this information before applying it to your situation.>> Several people have asked how did I know I was reacting to canola oil and vinegar...other than the usual diarrhea, etc. There are two proofs: 1. as a diabetic, I take my blood glucose [bg] several times a day. I noticed when I had those items in a meal, the bg reading was high. I tested them separately and they were the culprits. From a normal reading of 100, they would push up my bg readings into the 300 range, which is definitely not good. 2. I check with the pulse test for allergies...staying away from those foods for a week, I took my pulse, recorded it and then took a small amt of the suspected food, tested pulse again thirty, sixty and ninety min afterwards. Again, an allergic reaction was indicated by a increase in pulse rate of well over the ten percent which indicates an allergic reaction [You can check this out in the book DR COCOA'S PULSE TEST FOR ALLERGIES, which is in paperback]. Ann