MRS. KIM: They [the girls] could be anywhere, they could be doing anything. Smoking, or drinking, or buying drugs!
LORELAI: They’re at the movies. There’s no drugs there. They don’t even have the real Red Vines.
Red Vines is a brand of red licorice candy made by the American Licorice Company. The current flavour has been used since 1952.
Lorelai and Rory seem to be very fond of them as Lorelai said Dean had saved their movie night when he gave Lorelai the Red Vines she had forgotten at the supermarket. The Black-White-Read Bookstore apparently only sells generic red licorice.