Smoke

Inhaling smoke into the lungs, no matter the substance, has adverse effects on one's health. The incomplete combustion produced by burning plant material, like tobacco or cannabis, produces carbon monoxide, which impairs the ability of blood to carry oxygen when inhaled into the lungs.

There are several other poisons in tobacco that constitute serious health hazards to long-term smokers from a whole range of causes; lung cancer, heart attacks, strokes, impotence, low birth weight of infants born by smoking mothers.