I wonder if perhaps the hot flushes cause a drop in blood pressure, which in turn, causes the nausea. The rapid dilation of the smaller blood vessels which cause the flush (the capillaries) has to come from somewhere.... With me, I feel quite ill about half an hour after eating a meal. One of my other medical conditions affects the connective tissue body wide, and especially has damaged the interior walls of all my blood vessels. I've been told that this nausea is because the blood goes from other areas to my stomach and small intestines to digest the food...this causes the drop in blood pressure, which makes me feel quite ill.