Sources of medicines and their discovery Revision Notes | GCSE OCR Foundation Biology

What this lesson covers

Learn about how medicines are traditionally sourced from plants and microorganisms, including famous examples like digitalis from foxgloves, aspirin fro...

• Explain how traditional medicines were discovered from natural sources
• Describe the origins of digitalis, aspirin and penicillin
• Compare traditional plant-based medicines with modern synthetic drugs
• Evaluate the role of natural products in modern drug development

Key ideas to keep in view

Use this lesson to stay inside B6.3 Monitoring and maintaining health while connecting the detail back to the wider B6: Global challenges topic.

• B6: Global challenges
• B6.3 Monitoring and maintaining health
• GCSE OCR Foundation Biology

Lesson notes preview

Read the core explanations from Sources of medicines and their discovery before testing yourself from memory.

• Your medicine cabinet contains drugs that started life in a foxglove flower, willow bark, and mouldy bread. For thousands of years, humans discovered medicines by trial and error from the natural world around them.
• This journey from plant to pill reveals how scientific breakthroughs often happen by accident. The story of modern medicine begins not in sterile laboratories, but in gardens, forests, and even contaminated petri dishes.
• 2. The Heart Drug from a Deadly Flower
• Digitalis is a powerful heart medicine that comes from foxgloves - beautiful purple flowers that are actually highly poisonous. This drug strengthens the heartbeat and helps treat heart failure.
• A heart medication extracted from foxglove plants that increases the strength of heart contractions and is used to treat heart failure.
• The discovery happened in 1785 when physician William Withering noticed that patients with heart problems improved after drinking tea made from foxglove leaves. He spent years working out the correct dose - too little had no effect, too much was fatal.
• Aspirin, one of the world's most common painkillers, originates from willow bark. Ancient civilizations chewed willow bark to relieve pain and fever, not knowing they were using nature's own aspirin.
• The active ingredient is salicin, which the body converts to salicylic acid. However, this natural form caused severe stomach problems. In 1897, chemist Felix Hoffmann modified the molecule to create acetylsalicylic acid - what we now call aspirin.
• A painkiller and anti-inflammatory drug originally derived from willow bark, now synthetically produced as acetylsalicylic acid.
• This shows how modern drug development works: start with a natural product, identify the active ingredient, then modify it chemically to make it safer and more effective.

Continue through the topic

Move to the related lessons or back to the topic page when you need the wider sequence before exam-style practice.