Natural scents have been used for thousands of years in religious and burial rituals, as aphrodisiacs, to cover foul odours, etc. At the end of the nineteenth century the first human-made (synthesised) scents were introduced. Now there are over 1000 body fragrances, and scents have been added into products ranging from cleaning fluids to candles, and from tissues to disposable nappies. Most of these scents are synthetic.

There are now well over 3000 chemicals used in scents - some scents contain as little as 10, others as many as 100 - and many of these chemicals are known to cause illness: from asthma to cancer. What is not known are the effects of combinations of these chemicals, and this may be impossible to discover because of laws allowing manufacturers to keep their recipes secret.

Ed.- (i) One finding is that, the more synthetic chemicals a fragrance contains, the lower the quantity of each must be to avoid adverse reactions. One might therefore conclude that the safest fragrances are those which only use a single scent. Other research has shown that the scents in air fresheners, deodorisers, etc. are potentially carcinogenic.

(ii) The International Fragrance Review Association sets guidelines on safe levels of ingredients but the research is on the raw materials rather than on the combination of materials in final scents, and Association members are not bound by law to follow their body's recommendations. Some manufacturers carry out their own safety tests on finished fragrances.