Vampires hate garlic for a simple reason: We made them up. Over the course of several centuries, we've decided that they hate sunlight, crosses, and garlic. Historians can't give a definitive answer as to why we developed that folklore, but by looking at vampire mythology, we can make a few educated guesses.First, it's important to note that nearly every major culture has some sort of vampire myth, but descriptions of vampires vary greatly from one culture to the next. Our modern ideas of vampires are largely informed by Bram Stroker's 1897 novel Dracula and its film adaptations.Stoker's novel was the first piece of literature to use garlic as a vampire deterrent, but it's unlikely that the author simply added that for effect; garlic has been used to ward off evil for centuries. For instance, Ancient Egyptians believed that the herb had powerful magical effects, and Romanians have been obsessed with garlic for centuries. As Stoker set his story in Transylvania (a region in Romania), he likely borrowed from local legends when building his idea of the vampire.So, why garlic?Well, some researchers believe that vampire legends come from real-life diseases. Rabies, for instance, causes victims to become violent and agitated; to an uneducated observer, a rabid person might seem possessed by an evil force. Rabies also causes an aversion to strong smells."Infected people display a hypersensitive response to any pronounced olfactory stimulation, which would naturally include the pungent smell of garlic," National Geographic historian Mark Jenkins wrote.At some point in history, maybe someone noticed this effect--and started stringing cloves of garlic around their home to ward off the evil disease.That's one possibility, but as writer Kelsey Kennedy notes for Atlas Obscura, vampire myths don't necessarily need these types of medical explanations. Sometimes, people just make up stories, and those stories gain new details as they're passed down from one generation to the next.Kennedy believes that the simplest explanation is likely the most accurate: Someone came up with the idea that garlic wards off vampires, and they told the story in a compelling way. Other people repeated it, and that's how it ended up as a part of the vampire legend.Of course, we don't know that vampires hate garlic, since we can't exactly interview one. Since garlic increases blood flow and improves circulation, you'd think that bloodsuckers would love it--but maybe they prefer their food bland.