Ancedotal information abounds for all sort of motion sickness remedies.  Unfortunately most of these are not of any real proven value--at least under scientific double blind studies.  As Peter notes a side effect of high doses (and in some people even as low as 600 mg) of vitamine C will be gastrointestional upset, including diarrhea and vomiting.  There may be some slight antihistamine effect of vitamine C--but not enough to warrent its use in motion sickness.  Dramanine and Meclazine are the drugs of choice which have antihistaminic qualities.

My views for treatment and prevention of  motionsickness have been posted in T & T a number of times so I shall not repeat them at this point.  Suffice it to say, it if works for you--then use it.

Regards,

Bob Austin M.D.

Perhaps this has yet been mentioned but many offshore sailors swore by
Sturgeron, an over the counter blood pressure drug sold in Europe. When I
raced my 65' ultralight from Victoria, British Columbia to Maui, 2 out of
the 10 member crew who were particularly subject to motion sickness used
it with no side effects. But like all of the drug remedies these are
chemicals that are foreign to your body. In any event it worked well for
these 2 who had never been offshore before but had frequently been sick in
inshore sailing. But the highest winds we experienced were 40 knots and
once we got past the Washington and Oregon coasts and "turned right"
around the Pacific High at about the latitude of San Francisco it was all
downwind/offwind surfing between 15 and 20 knots which makes for a faily
stable ride.

Cheers,

Roger Elmes