For vomiting, yes. For diarrhea, ehhh not so much...but the jury is still out on that. It really depends what bacteria or virus has infected your gastro tract. With diarrhea, the main concern is the strain of E. coli that produces a toxin that can cause kidney damage if not treated...although this does not happen to everyone that is infected by that bacteria.

If you go to the ER for vomiting, chances are they will give you ondansetron (or a similar anti-emetic). In most people, this will stop the vomiting within 15 to 30 minutes and allow the person to drink fluids. Obviously, if it didn't stop, they would give you an IV.

The point here is that the toxins causing the sickness are unlikely to cause harm to your body if you block the 5HT-3 receptor they are binding to and activating. Vomiting as it relates to the gastro tract is controlled pretty much exclusively by serotonin and the 5HT-3 receptor.

For example, if you eat something and it irritates your stomach and small intestinal mucosa (not because of bacteria or viruses....think eating like a whole carolina reaper pepper or something similar that is irritating), certain immune cells will become activated by the inflammation and will release serotonin. That serotonin will then bind to and activate the 5HT-3 receptors which will directly stimulate the vomiting center in the brain. Obviously, the reason animals evolved this mechanisms was help expel noxious foods and make us adverse to them in the future.

Now, another example is food poisoning. There are many types, and I won't go into crazy detail. Let's consider the most common...Staph food poisoning. Certain strains of Staph that find their way into food (think somebody handling food with their bare hands) will grow and produce an emetic toxin (if the food is not stored properly). This toxin, if ingested, directly binds to and activates that 5HT-3 receptor...i.e. it directly activates the vomiting center in the brain. These bouts tend to be short in duration with no lasting effects. Therefore, taking a damn anti-emetic (like generic Zofran...ondansetron) is fine. All it does is bind to and inactivate the 5HT-3 receptor in the gut. It literally just blocks either serotonin or toxins from binding and activating the receptor.

So, the next time you are sick to your stomach and it is dragging on, call your doctor and ask for ondansetron. The huge benefit to this medication is that it normally works very well and will allow you to re-hydrate...and we all know that is the most critical part of gatro illnesses.