Doctors in Canada have called for a ban on the use of perfumes and aftershaves in hospitals and clinics. They say the chemicals in the scents can trigger asthma and allergies or make the situation worse than it used to be. The scientists were shocked to learn that over half of asthma attacks were caused by irritants such as powerful smells. Besides perfumes and aftershaves, these can include cigarette smoke, cleaning fluids and other strong fragrances and odours. Dr Ken Flegel and Dr James Martin of McGill University in Canada wrote about the dangers of smells in hospital in the Canadian Medical Association Journal. They said: "Hospital environments free from artificial scents should become a uniform policy, promoting the safety of patients, staff and visitors alike and the sooner we perform it, the better result we are going to get."

Strong smells affect many of us in one way or another. Around a third of people say they are physically affected by artificial scents worn by others. The doctors noted that this should be a serious concern in all hospitals. They wrote: "It is not that easy to believe, but the more artificial scents are designed to make us attractive, the more unintended harm can be done to those who are vulnerable. There is emerging evidence that asthma, in some cases, is primarily aggravated by artificial scents." They added that: "This is particularly concerning in hospitals, where vulnerable patients with asthma or other upper airway or skin sensitivities are concentrated." They warn that scents in hospitals can make these patients' condition worse.