TheGeneral asks:

I know [Bacchus] was wild, but he was on Aslan's side.. he wouldn't have harmed them would he?

Bacchus, when wandering crapulously, could get a little intemperate at times; his maenads, however, could become very scary when frenzied and would tear even dear friends apart limbmeal.

True, Deadman (feels wierd typing to someone with a name like that )
Also, though, I think it might have been that Bacchus could maybe get kind of...reckless. I guess. I'm not sure if, given Lewis' description, he would have actually imagined the Maenads tearing people to bits. They are magic-infused Narnians; therefore they must be good. I think.

I never really liked Bacchus. From what I have heard of him, he was not really a good 'person' in mythology. He was involved in pagan rituals that were not always the best. I am trying to be brief here... and these are just things I heard, and mere opinions. No hard feelings toward anyone.
Revel

I always felt that part was weird (having read mythology before). I don't know why Lewis put it in because I don't think it's really needed in the book. There's no real reason they're there. Aslan could have made grapes easily if he had wanted to.

I think it was more about setting things right. In LWW Tumnus talks about the old days before the Witch when Bacchus used to come every summer...when all was well in Narnia. But even after the children's reign, they haven't completely restored peace, because Bacchus hasn't showed up yet. In PC, he does, and it's all right again, I guess.
I didn't like him at first, but upon a further delve into myth, I do like him very much and I'd far prefer him above any old battle any day. I would have liked him to be there even without the inserted movie-battle.

True, it may not have been needed, but I agree with ChristProclamer, plus I thought it was cool how a specific myth in our world turned out to be real in Narnia (along with a lot of others too).

I missed this part, especially since they didn't do it in the BBC movies either. I was so looking forward to seeing them...

Correct me if my Greek Mythology is a bit off, but wasn't Bacchus associated with drunkeness? Maybe C.S. Lewis put that in their almost as a disclaimer to kids. Sort of like "Say no to drugs" type of thing. Then again, if he felt that was needed, he wouldn't have used Bacchus to begin with, would he? I think Lewis was just showing how wild and reckless Bacchus was; he wouldn't have ever harmed Susan or Lucy, but he was so crazy that the girls felt uneasy anyway.

Bacchus was not just associated with drunkenness be was the patron god of inebriation, ecstatic liberation, and other forms of licentiousness, and patron of the two Athenian dramatic festivals. In Roman mythology Bacchus is also identified with Pater Liber (i.e., Father Freedom).
I doubt very much that Lewis was trying to send an anti-drugs message, but I contend that the scene wherein Bacchus and his followers appear is meant to show that not only does the world of classical Graeco-Roman mythology intersect with Narnia, but that Narnia is a land of freedom and possibility. (It is also wittily allusive for those who are well-read.)
You may recall that Bacchus also makes several other important appearances in Prince Caspian (Ch. 14), wherein Bacchus particularly opposes authoritarian rigidity and conformity:

Aslan stopped right under the window [of the class with the tired looking teacher] and looked up at her.
“Oh, don’t, don’t, she said. “I’d love to. But I mustn’t. I must stick to my work. And the children would be frightened if the saw you.”
“Frightened?” said the most pig-like of the boys. “Who’s she talking to out of the window? Let’s tell the inspector she talks to people out of the window when she ought to be teaching us.”
“Let's go and see who it is.” said another boy, and they all came crowding to the window. But as soon as their mean little faces looked out Bacchus gave a great cry of Euan, euoi-oi-oi-oi and the boys all began howling with fright and trampling one another down to get out of the door and jumping out of the windows. And it was said afterwards (whether truly or not) that those particular little boys were never seen again, but that there were a lot of very fine little pigs in that part of the country which had never been there before.

The vines of Bacchus destroy the bridge which had constrained the river god; the prim and proper are frightened, the brutal are punished; the balance of nature is restored, and Caspian’s critically ill old nurse is restored to health by Bacchus:

“Here you are, mother,” said Bacchus, dipping a pitcher into the cottage well and handing it to her. But what was in it now was not water but the richest wine, red as red-currant jelly, smooth as oil, strong as beef, warming as tea, cool as dew.

Ultimately, Bacchus assists Aslan’s restoration of the natural world wherein the folk of Narnia can, by the end of the book, enjoy a great feast full of good things, enjoyment and freedom.

Random note of possible interest: Bacchus is actually the Roman name for the god. Dionysus is the Greek name.

I don't really like Dionysus/Bacchus as a rule, although I admit that in PC, Lewis made him more likable. I did like him when I first read the books, before I knew anything about Bacchus and the myths. And then when I learned about them, I was not sure I should like him so much. Because, like Deadman said,

Bacchus was not just associated with drunkenness he was the patron god of inebriation, ecstatic liberation, and other forms of licentiousness

I do love that scene in PC though, with the nurse and the schoolteacher and the boy who was being whipped and Guinevere (I think that's the school girl's name).

P.S."Brooklyn!"

Rising Star says:

Bacchus is actually the Roman name for the god. Dionysus is the Greek name.

Actually, Bacchus is Greek. (Well, it’s the Latinized version of Bacchos. Similarly, we tend, in English, to Latinize Achilleus as Achilles, Argos as Argus and Apollôn as Apollo.)
Bacchus, however, like most of the gods, was worshipped under many names.

The schoolgirl, who trots off with a couple of maenads, who help her remove some of her more unnecessary and uncomfortable clothing, is Gwendolen.

Gwendolen! That was it. Thanks

And also thanks for the tidbit about Bacchus/Dyonisus. It being Latinized into Bacchus makes sense, seeing as the Romans spoke Latin and the Greeks spoke, well Greek. I suppose the only two I really know are Bacchus and Dyonisus and Bacchus was used in my learning of Roman mythology and Dynoisus was used in my learning of Greek mythology.

But I guess it all comes down to the same guy.

P.S."Brooklyn!"

I actually like the scene with Bacchus in the book, and was quite sad it wasn't in the movie...

I don't know Bacchus from any mythology I've read about, but I've learned a lot from everyone, so I guess, thankyou!