A society used to medical marvels of the late 20th century might naturally assume that ancient medicine was a primitive affair. The reality, however, is somewhat different.

Ancient physicians had no miracle drugs to treat disease. There were no computerized X-ray or magnetic resonance scanners, or medical laboratories, to diagnose disease.

But they did an amazingly competent job of treating the sick and injured. Some of the medical technology developed in ancient times surpassed anything available in the modern world until the 18th century or 19th century.

A person living at the time of Christ's birth, for instance, might have access to better plastic surgery than someone living in Europe in the early 1700s. Modern plastic surgery began in the 1700s when British surgeons working for the East India Company saw the work done by Indian surgeons.

They used technology developed by Shushruta, a Hindu surgeon who probably lived around 100 B.C. Modern surgeons have never found better substitutes for some ancient techniques.

One is the pedicle flap, which involves freeing a flap of tissue from one part of the body and sewing it onto another to repair a defect. It was developed 2,000 years ago.

Cataract operations were done in ancient India snd Egypt, and became almost routine in ancient Rome.

In 30 B.C. the famous Roman physician, Cornelius Celsus, described the technique in his classic book,On Medicine. The operation, called couching was used into the 20th century.

Celsus's book was so good that physicians used it for more than 1,700 years. Claudius Galen (130-200 A.D.) wrote books on human anatomy that were best sellers for almost as long.

Galen, by the way, often gets credit for developing a never-surpassed diagnostic procedure, taking the pulse.

Long before Galen, ancient Chinese physicians realized that the pulse seemed harder in people who ate a lot of salty food. It may have been the first recognition of the link between too much table salt and high blood pressure.

Consider another ancient medical innovation: Brain surgery. It was done in the Stone Age, which ended around 3000 B.C.

Stone Age people did a kind of brain surgery which today is called "trephining." Trephining was the first known surgical procedure. It involves cutting a hole through the skull bone to relieve excess pressure. Stone Age surgeons probably did it to release "evil spirits" that they regarded as the cause of headaches or strange behavior.

Scientists have found trephined skulls, with neatly cut holes, dating to about 8000 B.C. On some, the cut edges of bone show definite signs of healing. It means that the patients lived for at least weeks or months after surgery.

Then there's acupuncture, developed in ancient China, rediscovered by Western medicine in the 1970s, and just given a partial endorsement by the National Institutes of Health (NIH).

People who did plastic surgery in India and cataract extractions in Rome 2000 years ago -- and brain surgery 10,000 years ago, helped build the foundations of our modern health-care system. Most amazing is how much they accomplished, with so little.