The painkiller aspirin originates from willow.

The idea

Aspirin is a painkiller and anti-inflammatory medicine whose discovery traces back to willow trees, particularly species such as Salix alba. Willow bark contains salicin, a compound that the body converts into a pain-relieving substance. Chemists modified salicin to make acetylsalicylic acid, the active ingredient in aspirin, which is more effective and gentler on the stomach than raw willow preparations. This example shows how a traditional remedy from a plant can be investigated, its active chemical identified, and a related medicine developed through chemical modification and testing.

What earns the marks

• Aspirin is a painkiller used to relieve pain and reduce inflammation and fever.
• Its origin is the willow tree, whose bark contains the compound salicin.
• Salicin is converted in the body to a pain-relieving substance, and chemists developed acetylsalicylic acid as the active ingredient of aspirin.
• The example shows that chemical modification can improve a natural lead compound, for example making it more effective or reducing side effects.

Common mistakes and how to put them right

• Saying aspirin is extracted directly as salicin from willow.

  Put it right: Willow contains salicin, and aspirin is acetylsalicylic acid developed from it.

• Confusing the source with the final medicine.

  Put it right: Willow is the plant source, while aspirin is the manufactured active compound.

• Assuming all willow bark is a safe medicine.

  Put it right: Raw plant material can be variable and harmful, so controlled purified doses are used.

Exam tips

• State the plant source and the drug together, for example 'aspirin, originally from willow'.
• Mention salicin as the compound in willow that led to aspirin.
• Explain one advantage of the developed drug, such as being more effective or better tolerated, rather than only naming the plant.