Perhaps our distant ancestors also tended to eat a small bite first, then proceed with other foods, before consuming the remainder? For that matter the drug wouldn't be absorbed all at once. If it is toxic better to eject whatever hasn't been digested than continue absorbing it. There's a bonus psychological side-effect: vomiting is not pleasant and the individual (if they survive) will be more likely to remember what they ate and how sick it made them to avoid it in the future.

I never want to do it, but it nearly always makes me feel much better. You can even get a sort of sense of calm or euphoria from vomiting. I can't say that it's pleasant, but if it were less gross and smelly it wouldn't be so bad... although the muscle contractions would still be hell on my under-trained abs.

I'm familiar with the sensation; it's enough to make you feel better, possibly even sober (if it was a drinking related episode), but the effect is unfortunately very temporary.

Oddly, I gather rats cannot barf, which is why coumarin works as rat killer.

I think your recollection is off by a little. Coumarin is an anticoagulant and damages rats' livers: https://en.wikipedia.org/wiki/Coumarin

You might be thinking of corn gluten meal, which kills rats by preventing them from absorbing water? It's sold as RatX: https://www.ecoclearproducts.com/pages/ratx-faqs

Disney World has a ride ( I think called Mission Space ? ) that spins you in an enclosed space to imitate acceleration in space flight

Lots of motion sickness warnings on that ride and there are two key mitigations in each seat:

1. A “cockpit window” lcd screen showing a POV video that tracks with the acceleration

2. A powerful fan impelling air at your face

Looking away from the screen, even for a moment, can cause immense nausea and iirc is advised against on the ride

Neat!

Though, seriously speaking, I don't know really. I think wind helps against car-sickness, and maybe more than in one way: sickness can be triggered by too much of CO2 in a bloodstream. It normally doesn't but I believe effects of disorientation and increased levels of CO2 are additive. So it is possible to be slightly disoriented (but not enough for a sickness), slightly deprived of fresh air (but not enough for a sickness), but to feel sickness because of a combined effect.

In a non convertible, your vision senses betray what your balance sense perceives (motion instead of stillness) and the body decides it’s time to throw up whatever poisonous stuff made you

Much less of an issue for me when I'm in front looking out the front window.

And it never an issue when your are behind the wheel. In this case nothing can surprise you, because any acceleration or rotation not just predicted by your brain, but directly caused by it.