upset tummy- a glass of flat coca cola
My mom used to say warm 7-up. Or some saltine crackers. A banana might help too.
On the other hand my grandma swore by a cuppa hot tea with a shot of Irish whisky in it. LOL
I have a massive problem stomach ulcers and mango smoothies with just mango, ice and water always feel good. Mangos are alkaline and help balance it out. Papaya is also good.
Also if you make a tea with any of the following: mugwort, parsley, ginger, gentian, calamus, centaury, cinnamon... stuff like that. I just suggest you don't mix all of them because that would taste pretty shitty.
As for nausea I find umi boshi oil works best with hot water.
I have a few others but those work best for upset stomachs/ acid reflux