Do black and milds contain pure tobacco?

[hgjjkgkg]

So i tend to smoke quite a bit of weed which im not really concerned about it... however when im drunk i like to mix some black and mild tobacco into my bong bowl. My question is; do black and mild's contain pure tobacco? I never smoke cigarettes, but i hear they have a lot of stuff in them other than tobacco... which seems a lot more unhealthy. So my assumption is that although its obviously not healthy, its at least a bit better than if i were smoking/adding cigarette tobacco. Is that correct?

Thanks.