On top of the list we can mention the control of infectious diseases. This has lead to immense improvement of health and average life span.

Mass immunization - has helped in eradicating number of diseases that were once rampant but don't exist today - smallpox, diptheria and polio are few of the diseases conquered by vaccines. Smallpox has been eradicated from this earth but diptheria and polio and some others do have their presence in under developed and developing countries.

Discovering how vitamins work is another important advancement. Finding out what vitamins do what has been a major accomplishment in understanding our diet and our health.

Cardiovascular risk factors: We’ve learned tons about fats, diet and exercise in relation to heart disease.

Rational drug design: Today, we no longer have to just try folk remedies and hope that they work. We study and test various compounds to see if they'll be effective. The safety and efficacy of drugs is of the highest standard. Rigorous testing is required before drugs can be prescribed, which protects us from trying anecdotal remedies that might be harmful.

Molecular genetics: As we unravel DNA – the genetic blueprint of life – we’ll learn how to treat or prevent many stubborn diseases.

Cancer diagnosis and treatment. We can already pinpoint and treat some cancers successfully and we’re learning more all the time. New drugs and drug delivery systems are in the pipeline that will help to turn the tide in the fight against this killer disease.

Organ transplantations. Some day we’ll probably clone organs that can be stored and used as needed. Meanwhile, heart transplants are almost routine compared to only a few years ago. Anti-rejection medications and new techniques are making transplants a common part of our health care system.

Diagnostic technology. We couldn’t even take someone’s blood pressure at the turn of the last century, we have machines that can peer into the body without using surgery.

Of course, there are a lot of other medical achievements that can be mentioned here. Humanity has gained tremendously from the advancement in the knowledge of the fuctioning of the human body during the last century ( rather present century ). At the turn of last century our knowledge of medicine was too little as compared to the present.