Question: What would possess a person to have her face injected with a poison so deadly it can be used in germ warfare. Answer: "It makes your face look fabulous," says Jennifer Bassey, 54, the libidinous Marian Colby of the ABC soap All My Children. Like thousands of others hoping to tame frown lines and facial wrinkles, Bassey turned in 1994 to botulinum toxin, the same stuff that causes the potentially lethal food-poisoning botulism. "If there was anything that could stop me frowning," she says, "trust me, darling, I'd do it." Over the past decade, Botox, as the toxin is marketed, has become a cosmetic surgery staple for close to 100,000 patients annually. According to Dr. William J. Binder, a Los Angeles plastic surgeon who has coauthored five papers on Botox, it is safer than its origin suggests. He spoke with correspondent John Hannah.

What exactly is Botox?

It's the trade name for botulinum toxin type A, one of several different toxins produced by Clostridium bacteria. This stuff is so potent that, in purified form, half a teaspoon could kill all of Great Britain. But it's also one of the safest drugs that we use.

How can it be safe?

We are not talking about injecting the bacterium itself. The toxin is a protein manufactured by the bacterium. You get food poisoning when you ingest the bacterium, which keeps on making hundreds of thousands of toxins. It's the overdose of toxins that can cause fatal paralysis.

How much of it do you inject?

For wrinkles, you will use 10 or 20 units per site, maximum 40. It would take three to four thousand units to make a person sick.

So how does Botox work?

When injected, it temporarily paralyzes the muscles underlying wrinkles like frown lines and crow's feet, smoothing out the skin on top. It inhibits the nerve terminal, so that the muscle will not respond. You literally can't frown after the treatment, but you don't lose sensation. The nerve is still there, and the end of the nerve eventually sprouts a new terminal.

How long does the effect last?

Anywhere from three to six months. In low doses, the treatment can be continued indefinitely.

How much does it cost?

It runs from $300 to $500 per problem area. That's expensive, but no more expensive than collagen injections, and there's less risk of an allergic reaction.

Is it painless?

Not necessarily. The 30-gauge needle we use is fine, but it is a needle. If people have an aversion to needles, we use analgesic cream.

What kind of negative side effects could a patient experience?

There is the chance of other muscles becoming involved. Eyelid drooping can occur if the Botox seeps below the eyebrow and hits the muscle that controls the lid, but that is very rare. And it's probably related to the injection technique—the placement or rate of injection. Eyedrops can reverse the Botox effect for about six hours. Otherwise the patient just has to wait until the nerve regenerates. Since 1990 I've had just one case of that happening.

Has Botox been approved for medical use?

It has been approved by the FDA for treating such conditions as crossed eyes and uncontrollable blinking. Since then it has been used for some 15 to 20 different conditions, including wrinkles. The FDA can approve a drug, but it's then up to physicians to decide how to use it and for what purpose.

So how do we know it's safe?

You can go back to 1989, when we started using it. That's almost 10 years of history. I have treated probably over 1,000 patients, and it is amazingly free of complications.

Would you use it on your wife?

I have used it on my wife many times. She loves it. She had her crow's feet done.