Herbal cigarettes (also called tobacco-free cigarettes or nicotine-free cigarettes) are cigarettes that usually do not contain any tobacco or nicotine, instead being composed of a mixture of various herbs and/or other plant material. However, Chinese herbal cigarettes contain tobacco and nicotine with herbs added, unlike European and North American herbal cigarettes which have tobacco and nicotine omitted. Like herbal smokeless tobacco, they are often used as a substitute for standard tobacco products (primarily cigarettes). Herbal cigarettes are often advertised as a smoking cessation aid. They are also used in acting scenes by performers who are non-smokers, or where anti-smoking legislation prohibits the use of tobacco in public spaces. Herbal cigarettes can carry carcinogens.