Eating the recommended five a day could be causing an annoyance to those who suffer with hayfever.
Research has found that fruit and vegetables can put sufferers at risk of oral allergy syndrome. This is a problem for the people allergic to birch pollen who make up for one in four of the UK's 16 million hay fever sufferers.
The charity Allergy UK has found that fod allergies can exacerbate hayfever symptoms, meaning that some people suffer all-year round.
"The protein in certain fruits, vegetables, nuts, spices, is very similar in make-up to the pollen from certain trees, weeds and grasses," Lindsey McManus from Allergy UK told Boots Web MD.
"During hayfever season, the body mistakes it, and sees it as an allergen that's causing a problem.
Some people allergic to grass pollen may also be affected by tomatoes, melon, wheat, barley and rye, oats and soya beans.
According to the research by Allergy UK as part of National Allergy Week, oral allergy syndrome was unusual 15 years ago but is now more common.
"People can have hayfever for years before they start seeing oral allergy syndrome symptoms. So they won't necessarily link the two together."
The symptoms are different from the sneezing, runny nose and itchy eyes linked to hayfever. "It is more like a food allergy with tingling of the lips and tongue and sometimes swelling of the mouth," Lindsey McManus explained.