I don't know about that one... :)

The one thing you wouldn't want to introduce is more acid to upset a
stomach.

I'd have to have some definitive evidence before I tried it.
I used to fish with my doctor who had been in the Navy and did
research on air and sea sickness. One day while fishing with a
tailwind the exhaust got the best of me and I decided to chum to
improve our odds - only time I've ever been sick on a boat. In the
midst of my chumming he insisted I drive the boat which was not tops
on my priority list at the moment. Once I was driving the boat he dug
around in the ice chest and handed me a dill pickle. I thought he'd
lost his mind but decided to follow doctors orders and the relief was
immediate. He said in their studies they found dill pickles to be one
of the best available quick relief remedies. I've always carried them
since for passengers and they've always worked. Another interesting
item from his studies was that most often, motion sickness was caused
by fear - usually deep seated sub conscious. Even though pilots loved
to fly there was often a fear of crashing in the back of their minds
which triggered air sickness for example. Don't know if those studies
held up over time (this was 30 years ago) but it sure explains those
who start tossing their cookies as soon as they lose sight of land.
Give the pickles a try if you or a passenger ever needs them - you
might be surprised.