Giner Ale and Canada Dry do well because in addition to the ginger, the carbon dioxide helps alter the acidity ballance in the stomach.
I carry crystallised ginger in my car because when I get a headache it is often accompanied by nausea - but nausea is all it is - usually. Drinks wouldn't last a week!
I have to say that ginger is not a wonder cure but it certainly raises the threshold and helps in moderate cases.
In my experience.

Placebo? What's a placebo?