Neither. An acid is a compound that is willing to donate a hydrogen atom while a base is an element that is willing to accept a hydrogen atom. Acid examples: HCL HBr HSO4 (notice they have hydrogen)...
Well, if you drop a large bag of it on your head, yes. It's not particularly poisonous and is in fact used as a food additive, though in fairly small quantities (it has a rather unpleasant taste in...