Air fresheners and aerosols can damage the health of babies and their mothers, UK research suggests.
Aerosol sprays can give off VOCs
Frequent use during pregnancy and early childhood was linked with diarrhoea and earache in infants and headaches and depression in mothers.
The culprits are volatile organic compounds released by such products, say the Bristol University scientists.
It might be safer to limit use in the home, they told Archives of Environmental Health.
Volatile organic compounds (VOCs) are irritants, and indoor sources include solvents, floor adhesives, paint, furnishings and cleaning products.
The researchers followed the health and development of 14,000 children since before birth.
When they looked at levels of VOCs in the homes of 170 of the children and interviewed 10,000 of the mothers about their use of air fresheners and aerosols, the scientists found some concerning trends.
In homes where air fresheners - including sticks, sprays and aerosols - were used every day rather than once a week, 32% more babies had diarrhoea.
The babies were also more likely to experience earache.
Daily use of aerosols such as polish, deodorant and hairspray was associated with a 30% increase in infant cases of diarrhoea, and also affected mothers' health.
These mothers who used air fresheners and aerosols daily had nearly 10% more headaches and were about 26% more likely to experience depression.
Lead researcher Dr Alexandra Farrow, now working at Brunel University, said: "People may think that using these products makes their homes cleaner and healthier, but being cleaner may not necessarily mean being healthier.
"Air fresheners combined with other aerosol and household products contribute to a complex mixture of chemicals and a build-up of VOCs in the home environment."
She said pregnant women and babies up to six months might be particularly susceptible to the effects of this, because they spend around 80% of their time at home.
"There may also be implications for other groups who are at home a good deal, such as the elderly.
"More research is needed, but in the meantime, it might be safer to limit use of air fresheners and aerosols in the home. Squeezing a lemon is just as effective at freshening the air."
Professor Roy Harrison, professor of environmental health at Birmingham University, said: "There is a body of research on VOCs in the indoor environment which links them with those kinds of symptoms - headaches and not feeling so good."
But he said: "The mechanism is not very well understood."
Most of the products could be regarded as non-essential and, therefore, might be avoided, he added.
Dr Chris Flower, of the Cosmetics, Toiletries and Perfumery Association, said: "Cosmetic products such as hairsprays and deodorants are required by legislation to be safe in normal use.
"Aerosol forms of these products are labelled with advice that they should not be used in confined spaces and current evidence shows these products are safe.
"We shall be looking into the new research by Bristol University to see whether people are following advice and whether additional advice may be required."
The British Aerosol Manufacturers' Association and the UK Cleaning Products Industry Association said: "While we encourage on-going industry research, we believe that Alex Farrow's claims were not justified.
"It is quite feasible that those suffering from depression use more air fresheners in an attempt to cheer up their surroundings and that those parents whose children are vomiting or have diarrhoea have simply used air fresheners to mask the smell."
The research was funded by government bodies and charitable research organisations, including the Medical Research Council and the Wellcome Trust, as well as commercial sponsors and US research institutes.