Discovering and testing drugs

The idea

Traditionally drugs came from plants and microorganisms: digitalis from foxgloves, aspirin from willow and penicillin from mould (Fleming). New drugs are tested for toxicity, efficacy and dose. Preclinical testing uses cells, tissues and live animals. Clinical trials then use healthy volunteers at very low doses, then patients. In double-blind trials neither the patients nor the doctors know who has the drug or the placebo.

1. Name the stage of testing.
2. State what it checks: safety, effectiveness or dose.
3. Explain why placebos and double-blind trials are used.

Watch out A placebo looks like the drug but has no active ingredient; comparing the two groups separates the drug's effect from the effect of expectations.