Wa alaykum salam wa rahmatuLlahi wa barakatuHu,

Cigarettes’ and other forms of tobaccos’ being cancerous is well-known, as is a tobacco user’s increased risk for lung cancer, heart disease, emphysema, etc, etc. For this reason, using tobacco is unlawful as is selling it. (Bughyat al-Mustarshidin p. 158, 321-33; Bujayrimi on Khatib v. 5, p. 233; Qalyubi on Mahalli v. 1, p. 69) It is necessary that one avoid dealing in tobacco; any profit had from it is devoid of blessings, goodness, and extremely disliked. (Bughyat al-Mustarshidin p. 158)

And Allah knows best.

Shafiifiqh.com Fatwa Dept.

Note: Also see the chapter titled “Tahrim At-Tadkhin” or “Smoking [the forbiddance of]” in the English translation of ‘Umdat As-Salik, known as “Reliance of the Traveller” by Shaykh Nuh Ha Mim Keller wherein he quotes both the ‘Ulama‘ of the past and of the (post) modern era holding the view that it is forbidden (haram).