Holidaymakers are being warned to check the rules on carrying medicines abroad to avoid falling foul of local laws.
The Foreign and Commonwealth Office (FCO) said some commonly-prescribed medicines were “controlled drugs” in certain countries.
In Japan, some cold remedies are banned while some sleeping pills require a licence in Singapore.
Travellers could risk a fine or even imprisonment if they break the rules, the FCO said.
The Foreign Office said it was becoming more popular to travel to countries further afield.
But according to a survey of 2,000 adults in the UK, only 33% of them would seek advice on medication rules before they travel.
Nearly half the population of the UK is on prescribed medication, meaning that around 21 million people could be risking difficulties.
Banned in Japan
Medication containing pseudoephedrine – found in over-the-counter medicines like Sudafed and Vicks – is banned in Japan.
And in Qatar, over-the-counter medicines such as cold and cough remedies are controlled substances and must be accompanied by a prescription.
Diazepam, Tramadol, codeine and a number of other commonly-prescribed medicines count as “controlled drugs” so the advice is to check the regulations in the country you wish to visit.
Failing to comply may result in arrest, a fine or imprisonment in many countries, including Greece and the UAE.
Other notable restrictions include:
The FCO said anyone traveling this summer should visit their GP at least four to six weeks before their holiday to check if any of their prescribed medication contained “controlled drugs” such as codeine.
Countries such as India, Pakistan and Turkey have a list of medicines they will not allow into the country.
The FCO recommends contacting the embassy, high commission or consulate in the UK of the country you’re travelling to for advice on the legal status of specific medications.
The gov.uk website has a full list of foreign embassies in the UK.