Coke is often touted as a popular remedy for an upset stomach. You’ve probably heard this before. Sip on some flat coke and your nausea will go away. Really? In this post, we will explore whether there is any truth to this idea.
To start with, there is no scientific research that supports the claim that flat coke, or any other soda for that matter (like ginger ale) can help ease a stomachache, outside of a very specific condition called a gastric phytobezoar. Before we talk about gastric phytobezoars, though, let’s address a few common assumptions that are made about Coca Cola.
Many people believe coke can help you replenish electrolytes if you have been vomiting or experiencing diarrhea. However, coke doesn’t have significant quantities of potassium or sodium, which are both helpful in restoring an electrolyte balance, and the beverage actually has far too much glucose (sugar) for it to be beneficial in rehydration. For more on this, see this article from the New York Times.
So, Coke is not going to cure your traveler’s diarrhea and it’s not really going to rehydrate you.
Does this mean coke has no use when it comes to curing your stomach ache? Well, let’s say that you don’t have a case of traveler’s diarrhea. You aren’t vomiting from food poisoning and you aren’t rapidly losing fluids. You just have a stomach ache. Perhaps you are a bit nauseous. You are not sick, perse. Things are just a bit out of whack.
In this case, flat coke (slight carbonation is fine and may actually help in this instance) may help you feel better. It may help you feel better because you have become habituated to it as a remedy, but also because it can help relieve some of the pressure and gas buildup that may be causing you to feel nauseous in the first place. Sometimes a burp is all you need to start feeling better.
Coca Cola is also capable of treating a gastric phytobezoar. This is a condition whereby indigestible plant matter gets lodged in the stomach. It can cause severe abdominal pain, nausea, vomiting and in severe cases, perforation and bleeding. Coca Cola has been shown to effectively treat this condition (see this paper for one example). While it is not clear exactly why the coke works in this instance, it likely has something to do with the corrosive properties of certain acids in the drink.
If you want to see evidence of the corrosive power of coke, just have a look at this video:
In conclusion, coke – flat or otherwise – is not going to cure the bacterial infection that is affecting your GI tract. It certainly won’t help with something more serious like a parasite or an amoeba. Also, if the stomach discomfort is due to a buildup of acid (i.e. if you have heartburn or GERD), coke will not help, and it may actually aggravate the situation.
Coke can, however, provide relief if your nausea is caused by something as simple as gas buildup. It can also break down indigestible matter that is causing blockage. Finally, as a feel good remedy, there may be a placebo effect that can allow for some relief.
Feel free to push back with your own anecdotes in the comments. Also, feel free to direct us to any evidence that we may not have come across or mentioned in the article.
UPDATE: Many people have added comments here suggesting that coke is more beneficial than we make it out to be in this article. This may well be true, but please, try to point us to some credible scientific evidence (outside of gastric phytobezoars, that is). Anecdotal evidence is valuable here, too, but we would really like to see something more substantial. Photo credit: flickr user funkyah