I want to quote the conclusion from the article approved by many Rabbonim (the link I posted before)
“Accordingly, this analysis must lead to the unambiguous conclusion that smoking is clearly and unquestionably forbidden by ???? and that this should be made known to all who care about the ???? and their health.
A final note is in order: People who smoke are not, ? ”?, doing so in an attempt to flout ????. In fact, most would dearly wish to quit, but shedding an addiction is no simple matter. While it is important to make clear that ???? prohibits smoking, it is also important not to condemn those who struggle with this issue. Rather we must offer our
full help and support to aid them in their quest for physical and spiritual health.”
END QOUTE
With regard to Marijuana, Rav Moshe tz”l said it is assur for a variety of reasons. See his teshuva on it for more details or look online where his teshuva is explained in English.