Essential oil diffusers could be a source of pollution in the home, the French food and environmental safety agency warned Tuesday.
ANSES said the popular gadgets, which are supposed to purify and freshen air, could have some unpleasant side effects.
It said that 1,400 cases of people being affected by the products were reported to anti-poison centers in France between 2011 and 2019.
Most cases were linked to accidents, like children ingesting oils.
However, undesirable effects were also reported from "normal use, with eyes, throat and the nose being irritated and also effects on breathing."
These irritations may be linked to phenols and ketones in the oils, which were "unsuitable" for use in air freshening sprays and diffusers, ANSES said.
However, the report said most of the symptoms were "not serious and rapidly decreased when people were no longer exposed" to the chemicals.
And ANSES also poured water on claims that essential oils can help guard against the coronavirus, saying they offered no protection.
It had earlier advised pregnant and breast feeding women and people suffering from respiratory problems to avoid using oils entirely.
The agency stressed that air freshening diffusers which "emit volatile organic compounds (COV) could be a source of pollution" in the home, particularly when added to COV present in furniture and cleaning products.
Even natural compounds like terpenes, which are present in ginseng, basil and cloves, can cause irritation, it said.
Three years ago another ANSES report found that air filters, ionizers and "cleansing" sprays could not be shown to be effective and could even sometimes be bad for health.
