Their jump is biochemical, mediated by proton-pump inhibitors, serotonin boosters & other drugs that have become permanent additives to many human bloodstreams.

Over the past half century, health-conscious, well-insured, educated people in the United States & in other wealthy countries have come to take being medicated for granted.

More people shift to the pill-taking life every year, to the delight of pharmaceutical manufacturers. Indeed, drug sales suggest how willing people are to pursue better living through chemistry.

Last year retail drug sales worldwide were $317 billion. In the United States alone, consumers spent $163 billion on drugs. In North America, the use of drugs that affect the central nervous system, antidepressants & others, increased 17%. No group has escaped. Last week the Centers for Disease Control & Prevention reported that 10 million children took prescription medication for 3 months or longer in 2002 & preschoolers, another study found, are now the fastest growing group of children receiving antidepressants.

This is a social change on the same order as the advent of computers, but one that is taking place inside the human body. Just 50 years ago, according to a report by IMS Health, a company that tracks the pharmaceutical industry, the two biggest-selling over-the-counter drugs were Bufferin & Geritol.

The prescription drug business was tiny. In 1954, according to IMS, Johnson & Johnson had $204 million in revenue. Now it is about $36 billion. In 1954, Merck took in $1.5 million in drug sales; in 2002, that figure was $52 billion.

To look at it in another way, Americans take so many drugs that some researchers Dr. Christian G. Daughton of the Environmental Protection Agency's National Exposure Research Laboratory in Las Vegas, for example are worried about the effects on the environment.

What does it mean if the sewers run rich with Zoloft? Or to be more precise, what might happen to fish eggs if the rivers soak up waste water with discarded & excreted pharmaceuticals & personal care products, like shampoo?

No one has the answer yet, but the idea that what runs through our collective bloodstream is a potential environmental hazard makes you look at your medicine cabinet in a different way.

In short, while the Six Million Dollar Man is still a fantasy, Pharmaceutical Man is already here & largely unnoticed. Swallowing a pill at a business lunch is likely to elicit little curiosity. A high-powered executive who did not have blood pressure or cholesterol problems might be suspect. There are concerns about the widespread use of antidepressants, but they do not seem to have affected sales.

In fact, the group of antidepressants that includes Zoloft is the third biggest class of pharmaceuticals by sales in the United States, totaling $11 billion in 2003.

Drugs in the top two categories statins to reduce cholesterol levels & proton pump inhibitors to prevent heartburn, gastritis, ulcers & other digestive problems had sales of about $14 billion & $13 billion, respectively.

Critics of the national medicine cabinet have noted that behaviors & physiological changes that were once simply aspects of life menopause, the inability to keep still as a child, baldness, decreasing potency in old men have been medicalized, turned into syndromes or diseases.

Dr. Thomas Szasz, a psychiatrist who in the 1960's defined himself as far outside the mainstream by arguing that mental illness was a myth, recently wrote a book called "Pharmacracy," about the invasive rule of medicine as it defines our lives.

Last fall, the President's Council on Bioethics issued a report called "Beyond Therapy: Biotechnology & the Pursuit of Happiness." The report included material on genetics & embryo selection, but it also addressed performance enhancement & behavioral drugs. One of its concerns was the way everything in life becomes a medical problem.

When new technologies, including drugs, come through doctors, the report said, many aspects of life become medicalized, raising concerns that "the pursuit of happiness & self-perfection would become part of the doctor's business."

The report also cataloged "other aspects of human life that formerly had little to do with doctors & hospitals: childbirth, infertility, sexual mores & practices, aspects of criminal behavior, alcoholism, abnormal behavior, anxiety, stress, dementia, old age, death, grief & mourning."

One might argue that any extension of medicine should be welcome. The prevention of heart attacks is obviously a worthy effort. Antidepressants can ease anguish, which for many people who take them is overwhelming. In many countries of the world, people would jump at the chance to worry about having too much medicine; they don't have nearly enough of it.

Yet some of the new miracles of the pharmaceutical industry are not intended to save lives, but to improve & prolong them.

Ana-Maria V. Zaugg vice president of corporate strategic planning for IMS Health, said that there were two streams of change in pharmaceutical research & use. Acute care is giving way to chronic or preventive care managing cholesterol levels rather than treating heart attacks, for example. At the same time, disease treatment is being extended to treatment whose goal is to increase well-being.

Drugs for baldness, incontinence, sexual performance & the effects of menopause may be included in the latter category. Both trends are expected to increase, Ms. Zaugg said.

Some areas that she is confident will grow are drugs to improve male sexual performance, anti-Alzheimer's drugs & drugs for incontinence & osteoporosis. If new psychostimulants & anti-obesity drugs appear in the future, she said, they will quickly take off. Compounds that increase intelligence & greatly improve memory will undoubtedly be best-sellers as well.

Whether or not the growing use of drugs has altered our essential humanity, there is now almost no bodily system that cannot be adjusted by them. Blood, respiration, the nervous system, hormonal regulation, muscles & bones, the cardiovascular system, reproduction, sexuality drugs are available to nudge them all in one direction or the other. It is not unusual for someone to begin the day with a cocktail of antidepressants, statins & blood pressure medications.

The result does not yet seem to be the epidemic of dull, well-managed emotionless humanity that some forecasters have worried about. For instance, among professionals in journalism & publishing in the New York metropolitan area, who no doubt take as much Zoloft per capita as anyone on the planet, it is no small trick to find someone who is either calm or happy.

Perhaps in the future, stronger drugs will produce the well-sedated zombies that will make the streets of Times Square disturbingly docile & well mannered, but it has not happened yet.

There are concrete results of the medicated life, however. Dr. Isaac Schiff, chief of obstetrics and gynecology at Massachusetts General Hospital in Boston, said he found that "most people, men & women who are in their 50's, are taking something every day."

He added, "One of the reasons is that our life expectancy has changed dramatically. Our whole concept of aging is very different."

Dr. Schiff said that many people in their 40's & 50's "are now taking medication to prevent diseases in their 70's."

In the case of osteoporosis, for example, the point of taking medication at age 50 is to prevent a hip fracture at age 75 or 80.

What that means for medicine is that as old problems recede, new ones arise. Dr. Neal L. Benowitz, professor of medicine & chief of clinical pharmacology at the University of California at San Francisco, said that doctors had seen a shift in "what you can expect to die from." There are fewer deaths from heart attack, he said & more from congestive heart failure, cancer & Alzheimer's.

One problem, of course, is that it is the well-off & the well educated who are most likely to take advantage of the many drugs available. Another is that need can be manufactured by advertising.

Even children know from television that if you are sad & worried, there is a pill for you. If you have heartburn there is a pill for you. It is a lot harder to find out that there are other ways to feel better, physically & emotionally, than taking drugs.

By & large, however, the pharmaceutical road is paved with pretty good intentions. The president's report addressed "the pursuit of happiness." A similar report on the dangers of computers & other hard technology might have a different subtitle the pursuit of power, perhaps.

Even the dystopian fantasies of cyborgs & the overmedicated are fundamentally different. Drugs are an easy way to contentment & the absence of pain even if they are ultimately unsatisfying. Hardware is something else. It enhances the senses, increases strength, adds weapons. As a cyborg, you can be your own telescope, your own computer, your own gun.

It may not be so bad that the pharmaceutical human is arriving first.