| CAFFEINE | Nitrogenous alkaloid compound with a stimulant effect first isolated by German chemist Friedlieb Ferdinand Runge in 1819 (8) |
| TONIC | Toni Collette starts with a stimulant (5) |
| ORATE | Speak of regret and the effect, first of all (5) |
| ATROPINE | Poisonous alkaloid compound obtained from deadly nightshade and related plants, used medically as a muscle relaxant (8) |
| HANOVER | Unpleasant after-effects first German left in royal house (7) |
| CAPSAICIN | Colourless alkaloid compound in chilli peppers responsible for their pungency (9) |
| EUROPIUM | Chemical element 63, first isolated by French chemist Eugene-Anatole Demarcay in 1901 (8) |
| THORIUM | Soft radioactive metallic element first isolated by Swedish chemist Jons Jakob Berzelius in 1828, atomic no. 90 (7) |
| MOLYBDENUM | Metallic element first isolated by Peter Jacob Hjelm in 1781 (10) |
| NITROGEN | Chemical element, atomic number 7, first isolated by Daniel Rutherford in 1772 (8) |
| BARIUM | Metallic element first isolated by Sir Humphry Davy in 1808 (6) |
| BENZENE | Industrial chemical first isolated by Faraday in 1825 |
| INSULIN | This hormone regulates the blood sugar levels; it was first isolated by two Canadian scientists on July 30, 1921 |
| POTASSIUM | Occurring in seawater and first isolated by Sir Humphry Davy in 1807, an element that derives its symbol "K" from the Latin "kalium" (9) |
| POLYTHENE | Most commonly produced form of plastic, first synthesised by German chemist Hans von Pechmann in c. 1898 (9) |
| ACESULFAMEK | Calorie-free sugar substitute, E950, discovered accidentally by German chemist Karl Clauss in 1967 |
| KRAFT | Type of strong brown wrapping paper invented by German chemist Carl F. Dahl in 1879; literally, 'strength' (5) |
| MENTHOL | A crystalline compound with a minty taste and smell that is used as a flavouring (7) |
| ARGON | First isolated in 1894 by Lord Rayleigh and Sir William Ramsay, a noble gas, atomic number 18 (5) |
| RADON | Chemical element 86, first isolated as 'radium emanation' by German physicist Friedrich Ernst Dorn in 1900 (5) |
