Cigarettes are tubes of tobacco (or other substances) encased in a paper casing, usually smaller than 120mm long and 10 mm in diameter. They are usually consumed by holding one end of a cigarette in one's mouth and igniting the other end.
Regular consumption of cigarettes made several species sick, depending on the contents of the cigarette. For instance, tobacco-made cigarettes hurt humans, Bajorans, Romulans and Vulcans. However, the Federation still gave cigarettes in their 24th century drug shops, citing that member races may use cigarettes for medicine. Illyrians were known to make use of replicators for cigarette manufacturing. (RIS Bouteina: "Quantic Return")