An examination is being carried out by a hygiene expert at a Caribbean hotel where dozens of UK holiday-makers have fallen ill during their stay.
The hotel is located on the north coast of the country
The guests who have been taken sick are staying at the Bahia Principe San Juan hotel in the Dominican Republic.
Tour operator Thomas Cook says "a considerable number" are suffering from the sickness and diarrhoea bug.
At least three people have required hospital treatment. The Federation of Tour Operators is now investigating.
Valerie and Andrew Bembridge from Lincolnshire paid more than £2,000 to stay at the hotel.
Mrs Bembridge fell ill first and was taken to hospital accompanied by her husband and their nine-year-old son.
"Obviously I was in a bad way and my husband started vomiting and came over with a fever. "Soon after he'd vomited my son went down with diarrhoea, so all three of us were retained in the hospital."
The Bembridges were discharged after two days and cut short their holiday to fly home.
But they claim hundreds of guests at the hotel complex have been affected by the bug and are desperate to leave but are still too ill to be declared fit to fly.
Sukki Chhokar is a lawyer with the firm Irwin Mitchell which is looking at the cases of 20 people who stayed at the hotel.
He told BBC News 24: "There are a number of complaints with regard to undercooked food, lukewarm food and a number of other food-related health and hygiene conditions, to the extent where whilst returning back from holiday people were lying in the aisles, vomiting into sick bags.
"A doctor had to board the actual aeroplane at Gatwick to treat patients before they disembarked."
A spokeswoman for Thomas Cook said it was working with the Federation of Tour Operators to understand the cause of the illness.
She said an independent consultant had been sent by the federation to the hotel to carry out a comprehensive hygiene review.
No-one from the hotel was available for comment.