‘Sweka’, ‘shamma’, ‘burdigan’, naswar’ and ‘basenja’ are different kinds of tobacco. ‘Sweka’ and ‘shamma’ are the most popular varieties consumed in Qatar. ‘Sweka’ consist of tobacco leaves, some chemicals like sodium bicarbonate, ash and soil. The most dangerous substance in ‘sweka’ is cadmium, which is also used in car batteries. Another chemical mixed in ‘sweka’ is arsenic, which is used for killing rats. Also mixed is hydrazine, which is also a toxic chemical. Unfortunately, most users do not know of the composition of ‘sweka’.