Smoking may be bad for you, but researchers and biotech companies are quietly developing pharmaceuticals that are decidedly good for brains, bowels, blood vessels and even immune systems -- and they're inspired by tobacco's deadly active ingredient: nicotine.

Nicotine acts on the acetylcholine receptors in the brain, stimulating and regulating the release of a slew of brain chemicals, including seratonin, dopamine and norepinephrine. Not surprisingly, the first scientific work that identified these chemicals and how they affect the body came out of nicotine research -- much of it performed by tobacco companies.

Now drugs derived from nicotine and the research on nicotine receptors are in clinical trials for everything from helping to heal wounds, to depression, schizophrenia, Alzheimer's, Tourette Syndrome, ADHD, anger management and anxiety.

"Nicotine is highly stigmatized -- and for good reason, because the delivery system is so deadly," says Don deBethizy, CEO of Targacept. "But the drug itself and the research generated by studying its effects on the brain both show great promise for helping us improve our physical and mental health."