There’s no sorrier sight than a puking preschooler. That’s the conclusion I recently reached around 2 a.m. as my poor 4-year-old heaved into the dim abyss. Luckily, her bout with the stomach flu was brief, and she was feeling better by the next day.

Stomach flu, also known as gastroenteritis, is a common affliction caused by bacteria or viruses that inflame the gut. Though mercifully short, the misery this brings is complete, for both the sufferer and the person charged with scrubbing chunks out of sheets, carpet and a stuffed toy cupcake.

So when presented with something that could potentially cut short the puking, any parent would jump at the chance. That’s the promise of probiotics, “good” bacteria (typically in pill form) that some people think might help restore the irritated gut and get kids feeling better faster. But according to two big studies (here and here) of puking kids and probiotics, parents should save their money for something else.

For both studies, scientists studied kids ages 3 months to 4 years who came to an emergency department with acute gastroenteritis. In addition to receiving regular care, these kids took either a probiotic or placebo for five days. Then the researchers tallied up the kids’ symptoms to see if those who got the live bugs fared better than those who received a placebo. Long story short, the scientists found absolutely no differences.

The trials used different bacteria as probiotics. One used Lactobacillus rhamnosus, sold as products such as Culturelle, and the other used that bacteria plus Lactobacillus helveticus, a combination sold as Lacidofil. Neither of the formulations cut puking or other symptoms short. The kids had about the same duration of diarrhea (about two days) and missed the same amount of daycare (two days on average).

As far as studies go, these results, both published November 22 in the New England Journal of Medicine, are pretty clear: Probiotics didn’t help puking kids feel better faster. Of course, it’s possible that certain types of probiotics are good for other things, as an editorial in the same issue of the NEJM points out. Scientists have been studying whether probiotics can curb colic in babies, with some hints that helpful bacteria may reduce crying in breastfed babies (though the jury is still out). Other bacteria might also help newborns at risk of developing dangerous infections, as a recent study on babies in rural India suggests.

But when it comes to gastroenteritis in kids, probiotics’ benefits don’t seem to be there. If you’re desperate and willing to throw money at the problem, go ahead and buy your poor puking kid some probiotics. There’s no evidence they hurt, and it might make you feel like you’re doing something. Still, you’re probably better off spending your money on juice and popsicles.