1. A good blister kit

This consists of anti-blister gel, and I lubricate my feet every morning. Also some plasters and tape, and a bottle of iodine as an antiseptic. I also use it to disinfect unboiled water. My first big roll of tape is running out, but I'm glad that through a mixture of prevention and early treatment, blisters have yet to really slow me down.

2. Some basic antibiotics

Treating water with the iodine, as mentioned above, is key to prevention. But when you are eating in local restaurants and people's homes, a few bugs are inevitable. I always carry Ciprofloxacin, which has always worked within 24 hours of taking it. But it's also important to have a proper check-up once I get home. As I discovered after cycling home from Siberia, dysentery can be stunned into inactivity, but can continue to live in one's guts.

Another antibiotic I carry is Doxycycline, which is both a preventative against malaria and can also be used to treat minor infections, such as infected blisters.

3. Anti-inflammatory drugs

For sore and swollen joints, I have off-the-shelf ibuprofen and also some stronger drugs recommended by my physiotherapist. I also have ankle and knee supports and bandages, which are handy for inflamed and sore joints.

4. Painkillers

These include some general ones such as paracetamol and also the much stronger (but potentially addictive) co-codamol.

5. Plenty of laxatives

You may smile, but it's no joking matter when you are walking across the Gobi for two weeks, and the only sight of a piece of fruit or vegetable you get is on the back of your laptop. When you get 'bunged up' for a few days or more, energy levels go down drastically, and all things in life seem mournful and depressing until you get some relief. That said, laxatives are dangerous things when you are sleeping in a tent and have to head out into the freezing cold to relieve yourself in the middle of the night when they finally kick in. The only things I haven't used in the kit are some anti-diarrhoea tablets and some antihistamines. But spring is just around the corner, so the bees and wasps and other stinging things will be out soon. So I have been making good use of my medical kit, which justifies its 500 gram weight in my pack.

As you may not have internet access to do research, it's important to keep the instructions for medications handy. I usually cut them out and store them in the kit. It's also very helpful to have a professional or two whose opinions you really respect, and who you can e-mail or call when you need advice.

Once, while cycling around Australia, having just crossed Papua New Guinea, I came down with a severe fever. The local doctor I saw in Melbourne told me it was the flu. My doctor friend, Aric, in Hong Kong, said it sounded like malaria. I went to the local hospital for a blood test, where they established that indeed it was malaria, and so admitted me and treated me properly.

Aric's long-distance diagnoses and advice came in handy once again on this trip for a tooth problem. I had to buy some additional antibiotics, which we were able to get easily at a Chinese chemist.

For other injuries, it's also worth having a connection to a physiotherapist and podiatrist - in my case Aaron Smith and Douglas Horne respectively, from Sports Performance in Central, who have given me advice by e-mail when I have suffered injuries.

I'm no doctor, however, which is why I suggest you seek professional advice before you pack your bag and head out on your expedition. But don't forget those laxatives.