[jaggederest]

Tobacco is the cause. Raw tobacco usage straight off the plant is cancer-causing, there's no manipulation needed.

[SapporoChris]

I will not disagree completely. But I will point out that nicotine by itself can actually have benefits that outweight the risks.

Search "benefits of nicotine", yields a wealth of articles supporting this such as: https://pubmed.ncbi.nlm.nih.gov/1859921/

[jaggederest]

Absolutely, there are few weight loss / irritable bowel syndrome drugs more effective, though it is of course horribly addictive. But tobacco is a lot more than just pure nicotine, and that's where the problems come in.