Being sickened by the taste, smell or even thought of a particular food or drink because, on a previous occasion you became ill shortly after consuming it. Your mind has made a connection between the food/drink and the illness although it was purely coincidental, and the food/drink item actually was not the cause of the illness.
You are dining on steak with Sauce Bernaise. Shortly after eating it you become violently ill. In fact you came down with the flu, and you would have become ill just then regardless of what you ate. Nevertheless, your mind connects the illness with the sauce bernaise, and ever after whenever you taste, smell, see or even think of sauce bernaise your stomach gets queasy because you think it was what caused you to get ill.