Why does chewing tobacco cause dizziness?

Nicotine poisoning. Tobacco contains nicotine. Some people are very sensible to toxic effects. Dizziness and nausea are toxic effects of nicotine. Chewing tobacco with result in mouth and throat cancer. Hope you are smart enough to realize you must stop.
Effect of smoking. The effect is more the destruction of the alveolus or the oxygen exchange apparatus so gases can become liquid and you can't breathe properly. Heat from hot smoke, caustic drugs in cigarette all lead to the destruction of the lungs. The point i make is, if smoking causes severe gum and bone loss around the teeth, the hardest structures in the body, when it goes to one of the most vulnerable, yikes.
It has nicotine,drug. If something makes you dizzy, it probably has a effect on your brain. If you don't like that happening, don't smoke. That is not good for you. You can guess that it either kills brain cells, and/or drugs you and/or suffocates you by eliminating normal respiration. I can think of no good effects from smoking.

Related Questions

Can the reason I'm getting dizzy be because I stopped chewing tobacco?

It could be. There are a number of symptoms of tobacco (nicotine) withdrawal, and dizziness and lightheadedness are two of them, together with anxiety, insomnia, irritability and others. However, it will pass, and if severe, can respond to nicotine replacement therapy and other methods of treatment. Stay quit! you are doing your body and mind a great favor, and don't let a few withdrawal symptoms stop you. Read more...