There's a lot of interest in the possible health benefits of wine, especially red wine. Some of this may just be wishful thinking because wine is so good and wine drinkers would rather it be healthy rather than just unhealthy.
There is good evidence that there are some genuine health benefits from drinking wine, but I'm not so sure that there are many health benefits from bathing in wine. The women of ancient Sparta though so, however.
On the same principle, Plutarch informs us, Spartan women bathed their newborns not in water but in wine to test their constitutions. He then reports the general view that bathing children in wine specifically throws epileptics and sickly infants into convulsions, whereas healthy children are tempered and strengthened in body by it.
Without knowing for certain, I suspect the Spartan mothers engaged in this practice because they understood the antiseptic properties of alcohol, and knew that the strong fumes would provoke some kind of physical reaction in the infants.
Magic in the Ancient Greek World, by Derek Collins
It's always interesting to see how ancient cultures used things as medicine which worked on some level, even though people didn't understand how or why. Quite a lot of ancient medicine may have had a foundation in superstition, but sometimes the "superstition" was merely an attempt to explain something that clearly worked and worked well.
I doubt, though, that Spartan women necessarily bathed infants in wine because they knew that wine had antiseptic properties. It's certainly possible that such knowledge played a bit of a role, but it's important to remember the place which wine had in ancient Greek culture. Wine was a product of both nature and civilization; it had a role in both physical pleasure and social philosophy. Baptizing infants in wine would have had cultural, philosophical, and religious implications that would have mattered even without the presence of antiseptic properties in the wine.