Have a female cat called tonic. She seems and act healthy,

Thank you,
Now to hear that she has vomiting overnight in the wee hours does make issues like GI infections, foreign bodies, or harmful ingestions less likely with Tonic.
Instead, we'd be most suspicious that of bilious vomiting syndrome. This is a condition that arises when the cat’s gall bladder jumps the gun, secretes bile before the cat has eaten and this abnormally enters the stomach from the intestine. This causes stomach upset and the cat will vomit contents of their stomach. Often we see it in the wee hours of the morning before breakfast and in cats that are otherwise well and not vomiting at other points in the day. In a way, it’s the gastrointestinal tract getting carried away in its anticipation to eat.
Now in regards ***** ***** these situations, we can find giving a later dinner, giving her small meal just before bed time, or leaving food down (if she isn't gluttonous) can halt this vomiting for them.
Though for more severely affected cats, we can give a small dose of an antacid at bedtime to keep the stomach settled overnight. If we need to do that, you can use a low dose of Calcium carbonate (20mg per kilogram of her weight) or have her local vet dispense a low dose Zantac for her (since the OTC tablets are too strong to use in cats).
Overall, Tonic's signs do sound like a reaction to bile in an empty stomach. Therefore, we can use the above changes to try to reduce that for her or speak to her vet about a trial on antacid at bedtime to offset this for her.
All the best, *****
PS- What a lovely girl with lovely eyes. :)
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