I haven't dyed or bleached my hair since... July? Henna is an herbal thing, there's nothing else in it except henna (unless you buy a kit instead of just the powder, which you mix with hot water & apply), and it's actually very good for your scalp/hair. Provided you aren't allergic or something . My hair/scalp felt great for that first week. It doesn't feel different now, just more flaking. Big flakes, too.
I haven't been using a shampoo or conditioner regularly in the past year or more. It could be my scalp's response to the water, or it could be something else. I have Yes to Cucumber, which is a fairly good natural shampoo/conditioner, so I guess I'll start using that every other night and see how that goes.