I feel that I must point out to Harald Gaier that, in bad cases of motion sickness, ginger has no effect and it is not a digestive problem. If you eat nothing at all you will still retch and bring up a little colourless fluid.
I have suffered from motion sickness all my life. The movement of my pram caused it as a baby. Every time the pram went down a hill, I turned green and no doctor could find anything wrong. I was two years old before my mother discovered that, every time I travelled, I became ill. While at school, I never went on outings or visits to museums. The school would not take me.
Every remedy known to man has been tried to no effect. Eyes play no part in this condition. If you shut your eyes, you feel far worse. However, I noticed that it did not happen on every journey I made. On one occasion, I was on a coach and, when it reached the motorway and went at a uniform speed, I immediately recovered and felt quite well for the rest of the journey. This gave me a clue to the cause, which is alteration of the speed of the vehicle. It is well known that a winding road is bad for this condition because the vehicle goes fast on the straight and slowly round a bend.
I am usually all right on a plane because it goes at a uniform speed. Thus, I have come to the conclusion that, to some people, movement of the floor signifies danger. When there is danger, the body prepares for flight. If you are preparing for flight, panting as you breathe may improve matters. I tried this on Euro star and found it successful. MEL Stoker, Epsom.....