But the risks are greatly reduced if the vomitor is in fact nauseous. 
My mother was another who pushed flat lemonade (like 7-Up). Ginger tea is another home remedy that’s recommended. Oh, and for consistant nausea, there’s always Preggie Pops - they’re recommended for morning sickness, but also say:
Ginger is apparently not recommended for pregnant women, but is a Preggie Pop flavour nevertheless.
having just had a week of gastric 'flu i can tell you what does and doesn’t work.
doesn’t work: water, tea, sweet things.
does work: 7-up, coke, whiskey and milk (in the same glass), wheaten bread, crackers, banana, yoghurt, plain brown rice.
but before i could eat any of that i made this.
in a cup of water, dissolve:
1 tsp low sodium salt (for potassium)
3 tsp sugar (for energy)
add a squeeze of lemon juice, and slice of ginger.
boil it. cool it. drink it.
it was the only thing i could keep down at first, and it saved me from a trip to the ER for IV fluids and an anti-emetic.
if you find (as i did) that it’s 24 hours since you started vomiting, and 36 since you ate or drank anything, and you have muscle cramps and joint pain, consider the ER if you don’t get some potassium and sugar into you within an hour.
I was just reading that rats are unable to vomit, and when they’ve eaten something distressing, they search out and consume clay.
Clay would absorb all sorts of toxins, so it makes a kind of sense.
I go with whatever I feel like. I figure if I’m not hungry, I won’t eat, and if I am, I probably wouldn’t crave something that was going to make me throw up.
My mum was a big believer in the flat lemonade theory, but I must say, I don’t think it works… It’s too sweet for me, when I feel bad. She was also convinced that anything dairy was bad, which sucks, because quite often I crave yoghurt after being sick, which was forbidden when I was growing up.
When I was throwing up in Japan, my host mother gave me a rice mixture with soya and the yolk of a raw egg stirred through it. While it didn’t settle my stomach (not surprisingly, I found out later my throwing up was due to cysts on my ovaries, so I don’t think anything would’ve helped much) I did find out a new dish to polish up the leftover rice. Mmmmm, give it a try, it tastes nice, and usually disgusts friends and family !
So my vote is on “whatever you are craving” though I would ignore any junk food cravings when you are just starting to get over it. If you are craving sweet stuf, I’d have some honey and lemon tea, not ice cream, if you’re craving salty stuff, I’d have a tomato sprinkled with a little salt, rather than a packet of crisps !