They not only fill the air with weird and wonderful perfumes but some people say aromatic plant extracts can cure all sorts of aches and pains. Inside each bottle of oil is a pure liquid plant or resin distillation and it's these oils that aromatherapists believe will work wonders for your health.
Our reporter Michael Slater is going to sniff out the truth and find out if aromatherapy actually works.
Now we can't do them all, so we're going to look at one of the best-known aromatherapy oils lavender.
Belinda Wilson has been a fan for 12 years and is now using lavender with her kids: "I've always put a drop of lavender in their bath at night, just a really small amount in their bath. Often with my kids I'll put a drop of lavender oil on just a tissue and pop it underneath their pillow to help them relax and to calm down and to sleep at night time, it's always worked really well for me."
That comes as no surprise to aromatherapist Robyn Minski who says that: "Lavender does have properties which are central nervous system sedatives, and that's why it's most appropriate to use for conditions such as insomnia and stress and anxiety."
So big wraps for lavender oil then, but let's search for some science behind the sell.
We're going to find out if lavender can affect brain activity. At the sleep and chest disorders centre in Sydney volunteers Clint and Tim will spend 15 minutes in a room with no lavender oil aroma. That's long enough to see if it'll affect their brain activity. Then we'll put them in a room with a lavender oil burner to compare how quickly they relax.
To measure how relaxed they are, we've called on the services of Dr C Shu Chan who has been practising sleep medicine for the last 26 years, including measuring the brain's alpha waves.
"Alpha waves" are key to this experiment because they can only be detected when a person is in a relaxed state.
Test one: without lavender
First up, Clint and Tim settle down in the unscented room.
Dr Chen and his associate, Jocelyn will monitor how quickly the men's brains start to produce alpha waves. But, already, there's a problem.
"Clint has actually fallen asleep, he's actually not supposed to, but he has already gone to stage two of sleep," says Jocelyn.
Clint went straight through an alpha state into a snoring state!
"I'd better wake him up, he shouldn't be sleeping," says Jocelyn.
They've had their 15 minutes in the control room, next up it's the room with lavender.
Hard to imagine Clint could be any more relaxed, but how will Tim go? Supposedly, lavender oil can sedate his central nervous system, but will it?
Test two: with lavender
Dr Chan and Jocelyn will compare their alpha wave readings with the ones they got earlier in the unscented room. If the boys achieve an alpha state faster in the lavender room, it might just prove it's a stress-buster.
But again there's a problem.
Clint has fallen asleep again! So he's no longer valid in the study because his alpha waves can't be compared.
But what about Tim? Did he move into an alpha state faster? Apparently not.
Certainly, from the two studies that we've done comparing the inhalation of lavender, what we can say is that out of the two volunteers one of them showed exactly the same alpha rhythm in both studies with or without the lavender," says Dr Chan.
So apart from finding out that Clint could probably sleep standing up, there was little to learn from that test. So it's time to ramp things up and do another test with more stressed out people for a longer period of time.
Test three: a week with lavender
Meet our three new stressed-out test subjects: Manuela, Russell and Donna.
Manuela has two jobs and she also feels like a baby sitter to her two kids.
Russell is a psych nurse who works with adolescents.
Donna is a PA in an engineering company she's flat out, but thinks she's coping.
Manuela, Russell and Donna are going to use lavender oil on their skin three times a day. Each has been given a roller with a five percent solution of lavender oil. They'll also fill in a questionnaire about their psychological state which they'll do again after their week of lavender.
But GP and sceptic Dr Richard Gordon is certain our three will be just as stressed as they are when they began the test, because he says aromatherapy doesn't work.
"Some people think that it can alter the course of an illness by influencing your brain, by the smell coming into your head, but there's no science behind it," says Dr Gordon.
A week later, it's results time.
Before they started their stint with the roll-on lavender oil, our test candidates filled out a psychological questionnaire. They filled out another one when their week was up to see the change in their state of mind.
Psychologist Simon Forbes has analysed the data and has got the numbers in terms of the depression, anxiety and stress scales.
Manuela got off to a slow start with the lavender oil, but she persevered and it began to pay off.
"At first I thought to myself 'I've got a headache, I'm not really enjoying this'. By the third day I really felt relaxed, terrific and I could feel that it was starting to have an impact in a very positive way."
It's success and a good result for Manuela.
"When you started, the form you filled out in the beginning on the depression, anxiety and stress scale revealed that your level of depression was in the moderate range. After the aromatherapy though, what happened was that your level of depression, anxiety and stress all came back into the normal level. Hopefully you can have a much more positive experience from here," says Simon Forbes.
So Russell also found lavender oil reduced his stress.
"Initially [it was] quite good but after half-an-hour of inhaling I started to get little headaches," says Donna.
So for Donna, the lavender wasn't such a great success. Then again, her stress levels were pretty low to start with.
So the bottom line for lavender oil as a de-stresser? Well, two out of three ain't bad. It does seem to have a sedating effect, just like aromatherapists promise.
Lavender is just one of many essential oils on the market. But can our noses distinguish between them all? Well, if your nose is working it should be able to distinguish 10,000 smells. There are only hundreds of essential oils available so you should have no problem telling your primrose from your parsnip.