This is on the Mayo Clinics website..
While research about hookah smoking is still emerging, evidence shows that it poses many dangers:
Hookah smoke contains high levels of toxic compounds, including tar, carbon monoxide, heavy metals and cancer-causing chemicals (carcinogens). In fact, hookah smokers are exposed to more carbon monoxide and smoke than are cigarette smokers.
As with cigarette smoking, hookah smoking is linked to lung and oral cancers, heart disease, and other serious illnesses.
Hookah smoking delivers about the same amount of nicotine as cigarette smoking, possibly leading to tobacco dependence.
Hookah smoke poses dangers associated with secondhand smoke.
Hookah smoking by pregnant women can result in low birth weight babies.
Hookah pipes used in hookah bars and cafes may not be cleaned properly, risking the spread of infectious diseases.
Hookah is worse than cigarettes.