Going to a foreign country can be daunting, as even straightforward everyday tasks may suddenly require learning a whole new set of steps. Just the strain of daily life can become stressful. In addition, you are likely to be exposed to new and potentially dangerous bugs for which your immune system will be unprepared. It is wise to have a check-up at your clinic before you go, and to ask about any extra precautions you need to take. If you are currently using any medications, ensure that you take an adequate supply with you, as they may be hard or impossible to obtain abroad. Medicines should be clearly labelled, and, at some countries' customs and immigration points, it will help to have a doctor's letter stating that you need the treatments. There’s a lot more information on travelling with your medication in the chapter Travel.

It is sensible to research local medical facilities before travelling to another country, particularly if local medical care is likely to be relatively poor.

Make sure that you have the right travel and medical insurance. Most policies won’t cover medical conditions that you know were aware of when you took out the policy. For more on travel insurance, see the chapter Travel.

Coughs are a common problem among travellers, and you may be at particular risk during air travel, when large numbers of people are confined in a small space, breathing recirculated air.

Travellers' diarrhoea is usually caused by the contamination of food or water with faecal bacteria by people who have not washed their hands. It affects about 40% of travellers to developing countries, even when they have perfectly intact immune systems, and can be a particular problem for people with HIV. The most common cause of diarrhoea after travelling is giardiasis, which can be treated quite easily in people with HIV.