f you have had your Mexican holiday ruined by a bout of 'Moctezuma's Revenge', you could be the ideal candidate for a new study into travellers' diarrhoea.
One US vaccine manufacturer is offering a novel incentive for people willing to take part in a drug trial for a remedy for 'holiday tummy'.
Up to 900 volunteers can apply for a free holiday in Mexico or Guatemala to the value of £1,400 - and all they need to do is eat, drink and see if they get sick.
Accommodation in three-star hotels is included, as well as flights, and travellers can go where they like - as long as they are within three hours of test centres where they can provide blood and stool samples if they are struck down with a stomach upset.
The trips are being billed as 'almost like going on a package holiday', and recruitment clinics are opening up in London, Manchester, Birmingham, Belfast, Glasgow and even Reading.