The best tips for travellers

Inflight

· For those allergic to aspirin, use clopidogrel when trying to prevent a DVT. This works in the same way and should be used by any asthmatic, where aspirin could bring on an attack. This will require a prescription from your GP.

· Any child old enough can have their ears equalised on descent by blowing gently into a balloon.

· Anyone carrying essential medication in to countries with a strict drug policy, such as diabetics, should have a note translated into the local language to explain its uses.

At sea

· Regular sufferers have will a better chance of avoiding sea sickness by actually looking at the waves so that the boat's rocking can be anticipated.

· Most over-the-counter sea sickness tablets are also sedatives, so make sure you are not likely to be driving or diving on arrival at your destination.

· A good alternative to sea sickness tablets is ginger. In biscuits, tablets or tea, it can help reduce nausea.

· If you are going to be sick overboard, check the wind direction first.

· On smaller boats, it is wise to take your own travel medical kit, as those on board can be quickly depleted, and you can be a long way from a pharmacy.

In the heat

· There is more to fluid loss than straightforward sweating. The wind in dry environments and upset stomachs can make you lose even more. So drink plenty of water.

· If you do get diarrhoea, then electrolyte-replacement sachets are the best. However, a flat sugary drink, such as cola, with a bit of added salt can be a good, quick alternative.

· Water purified by tablets can taste awful. Fresh lemon or lime juice can make it more palatable.

· For anti-malarials to be 100% effective, you must avoid being bitten by a mosquito. Use nets, take Vitamin B capsules and wear long trousers and shirts to be sure.

In the cold

· The first sign of cold exposure is a dulling of the senses. Even if you are sweating, keep warm and keep both your head and chest covered.

· Altitude sickness is worsened by smoking, alcohol and exercise. So allow at least two to three days to acclimatise.

· If you ascend too quickly and notice shortness of breath, slow down, descend, or even wait a day until you feel stronger.

On your return

· The incubation period of malaria is up to two weeks. You must keep taking your tablets for the recommended period on your return. If you feel as if you have a flu-like illness, tell your doctor about your travels and insist on a malaria blood film being carried out.

· After suffering a bad case of traveller's diarrhoea, it can be several weeks before all returns to normal.

· Avoid excessive dairy products if you still feel unwell.

· There are now many specialist medical centres that deal with the returning traveller and their medical problems. They may be better than a quick NHS consultation.

Ask the flying doctor If you have any questions you want to ask Dr Jules Eden, email travel.doctor@theguardian.com, or write to The Flying Doctor, The Guardian, 119 Farringdon Road, London EC1R 3ER.