Transcript: Medicine 101

Hi, I'm Tony Hughes, a pharmacologist, and I'm here to tell you what we've learned about medicines since the Middle Ages.

Back then, remedies for disease were mostly plant based, but often bizarre. They might have been administered by a spell-chanting witchdoctor, and sometimes did more harm than good.

One so-called cure for malaria was a mercury based powder called calomel. Doctors in the 1800s consistently prescribed calomel for at least 40 years, with deadly results. We now know it's toxic, and not to be messed with.

But medical professions at this time made an important realisation: that a plant's effect on a patient were brought about not by magical forces but by the chemicals it contained. The business of extracting active chemicals from plants then began, and the science of pharmacology, which looks at the effects of chemicals on the workings of the body, was born.

Advances in knowledge and technology soon let pharmacologists not only extract and use the active chemicals from plants, but to start making those active chemicals from scratch. New synthetic, or man-made, chemicals appeared and medicines to fight micro-organisms and bacteria in the body were created.

And discovering the ways in which medicinal chemicals and the body's natural chemicals interact with one another was the next big pharmacological breakthrough. Enter the receptor concept.

That's the theory that special molecules in the body called receptors are responsible for allowing every medicine to work. It's a bit like a lock-and-key system, where the receptor is the lock, and the medicine, the key.

But a few important things need to be considered before any medicine is even administered.

The first is the method of administration. Modern medicines are delivered in a variety of ways. The aim is to get the active chemical in the medicine to the receptor site as effectively as possible.

The second important thing is the dose of the medicine. If it's too small, the medicine may have no effect at all. If it's too large, then side effects might start to be a problem.

Pharmacologists now know that every medicine has side effects, and identifying those which least affect the body in unwanted ways is often their greatest challenge.

In the most recent century, medicinal discoveries and developments have abounded. And today we're so far advanced that, well, there's hardly any need to prepare 'mummy powder' any more!