Kate Grenville had always associated perfume with elegance and beauty. Then the headaches started. Like perhaps a quarter of the population, Grenville reacts badly to the artificial fragrances around us: other people's perfumes, and all those scented cosmetics, cleaning products and air fresheners. On a book tour in 2015, dogged by ill health, she started wondering: what's in fragrance? Who tests it for safety? What does it do to people? The more Grenville investigated, the more she felt this was a story that should be told. The chemicals in fragrance can be linked not only to short-term problems like headaches and asthma, but to long-term ones like hormone disruption and cancer. Yet products can be released onto the market without testing. They're regulated only by the same people who make and sell them. And the ingredients don't even have to be named on the label. Perfumes -- Health aspects. | Odors -- Analysis. | Perfumes. | Perfumes industry.