Question 103: What is the Islaamic ruling on those who smoke cigarettes and when they come to the Masjid (mosque) they merely rinse their mouths with little water without performing Wudoo’ (ablution) again, under the pretext that they had already performed Wudoo’ before smoking. We know that cigarettes are of the foul things which invalidate Wudoo’, but we do not have enough evidence on this.
Answer: All praise be to Allaah Alone, and peace and blessings be upon His Messenger, and his family and Companions! Smoking is Haraam (prohibited). Those who afflict themselves with the evil habit of smoking should cleanse their mouths when going to the Masjid to remove the foul odor, so that others will not be harmed or offended. However, smoking does not invalidate Wudoo’... read more here.