* A lot of our current drugs were discovered by studying plants and micro-organisms (This is because plants produce a variety of chemicals to defend themselves against pests and pathogens).

* The heart drug digitalis was developed from a chemical found in foxglove plants (pictured).

* The painkiller aspirin was developed from a chemical found in the plant willow.

* Penicillin was discovered by Alexander Fleming from the Penicillium mould. (Fleming was clearing out petri dishes containing bacteria when he noticed there was also mould on the dishes. The area around the mould had no bacteria in it – he found that the mould was making a chemical that killed the bacteria – this chemical was penicillin)

* Most new drugs are synthesised (made) by chemists in the pharmaceutical industry. However, the starting point may still be a chemical extracted (taken) from a plant.

Vaccination and the sources of medicines.