It's your worse nightmare, when you lay that weary head down to rest, that pillow is literally festering!
A new study has discovered what we really didn't need to know, that the average pillow is home to a host of potentially-harmful fungi.
A British research team from the University of Manchester found as many as 16 types of fungi in pillows they analysed.
According to the researchers feather pillows had fewer species than synthetic versions, particularly in the case of a fungus which exacerbates asthma.
Although experts advise disinfecting pillows they say fungi occur in most environments.
Apparently the fungal spores found in the pillows feed off human skins scales and dust mite faeces.
Although the fungal contamination of bedding was first uncovered by studies carried out in the 1930s, few studies have been done since then.
In the study samples were taken from 10 pillows, five feather and five synthetic, all had been used for between 18 months and 20 years.
Researchers found that all 10 pillows had a "substantial fungal load" with between four to 16 different species being identified on each.
The microscopic fungus Aspergillus fumigatus was particularly evident in synthetic pillows.
This fungus commonly invades the lungs and sinuses and can worsen asthma.
It is also known to cause infection in leukaemia and bone marrow transplant patients.
The team also found pillows which contained fungi as diverse as bread and vine moulds. Some also had fungi which would usually be found on damp walls.
Lead researcher Professor Ashley Woodcock said the findings showed there was a "miniature ecosystem" operating inside pillows.
He says as people spend a third of their life sleeping and breathing close to a potentially large and varied source of fungi, the findings have significant implications for patients with respiratory disease, in particular asthma and sinusitis.
Dr Geoffrey Scott, chairman of the Fungal Research Trust, which funded the study, said the findings were interesting, and particularly relevant for asthma patients.
As these fungi are found in the environment, everyone is exposed to them.
He advises disinfecting pillows and buying feather ones to help reduce the exposure.
The charity Asthma UK say they are aware that patients at the severe end of the spectrum of asthma are more likely to be hypersensitive to fungi than others with asthma.
The study is published in the Allergy journal.