It depends on the reason for your upset stomach. Many reasons involve an excessively high PH , which means higher acidity. In this case you would take something with a LOW PH such as tums, which is sodium bi-carbonate. Vinegar has a high PH and will most likely not solve your ailment in this scenario.
Either way refer to this handy guide
http://www.ehow.com/how_16011_calm-upset-stomach.html
I believe many of the "uses" of vinegar are wives tales and myths.
[EDIT] The above answer was incorrect. Acidic indigestion happens when the stomach pH is too LOW, not high. Low = acidity, High = basic. Tums itself does not have an acidity, it is a buffer that reduces acidity (aka RAISING pH) to stop acidic indigestion. Vinegar is a base, and would have the same net effect in this case. This is also called heartburn when it travels up the esophagus.
However, it could be the reverse, too high pH will slow digestion and cause indegestion. If it's this case, then acidic beverages would help; citrus fruits, soda, and tea will usually calm that. I call this "iron tummy" because it feels like your stomach has turned to iron, but that's not medical.
It's unlikely a shot of vinegar would cure it (it's too basic and will throw stomach pH all over). You'd be better off taking antacids (which buffer the pH so it doesn't bounce around). Soda helps me the most. To each his own.
because of the sodium content.
good for digestion. settle upset stomach aches.
If you have an upset stomach, by having a bowl of plain white congee will settle down your stomach.
Crackers can help settle an upset stomach for some people, as they are bland and low in fat, making them easy to digest. They can also help absorb excess stomach acid and alleviate nausea. However, individual responses may vary, and it's essential to consider the underlying cause of the upset stomach for effective relief. If symptoms persist, consulting a healthcare professional is recommended.
It tastes goodHelps wake someone tired upCan help to settle an upset stomach
Over the years the best way for me to settle an upset stomach was gatorade... Drinking water is the worst thing to do
Metabolic alkalosis.
Soda water and bitters can help alleviate an upset stomach by providing relief from gas and bloating. The carbonation in soda water can help to settle the stomach, while the bitters can aid in digestion and reduce nausea. Mixing the two together can create a soothing drink that may help calm an upset stomach.
I had an upset stomach. He upset me greatly.
From past experiences it has almost always upset my stomach in a bad way.
some time there are bad things in the food that make you stomach upset
Heartburn is an acidic feeling in your chest, throat, maybe stomach area, while an upset stomach is only a pain or uncomfortable feeling in your stomach.