The most common food-related illness for travellers is diarrhoea , possibly accompanied by vomiting or a mild fever. Its main cause is a change in diet whereby bacteria you're not used to are introduced into your system. In many cases, the condition will pass within a few days without treatment. In the meantime, rest up and replace the fluids you've lost by drinking plenty of water - or for persistent diarrhoea - an oral rehydration solution, readily available from your home pharmacy, should do the trick. Barring that, you can make a home-made solution by dissolving half a teaspoon of salt and eight teaspoons of sugar in a litre of boiling water. If symptoms last more than four or five days, or if you are too ill to drink, seek medical help immediately.

Travellers should note that dairy products aggravate diarrhoea and should be avoided