Cough

I have learnt a lot about coughing over the last few days. Most coughs are triggered by a receptor that links to the vagus nerve. That receptor responds to hydrogen ions, capsaicin (the lovely stuff that is the main 'hot' component in peppers), and other vanilloids. You eat acidic, spicy food, you cough. Even fruit juice will trigger it. Ha.

It isn't always clear that you should suppress a cough if the cough is beneficial. Most of the time, it's just doing its job – expelling irritants at something like the speed of sound. If you try to suppress it physically (say, by keeping your mouth shut and closing your nose) the blast effect can be painful.

However, you can try to suppress it chemically if that helps your social life, or if you have some other fundamental reason for not wanting to cough. Dextromethorphan is normally the drug of choice. It's found in cough syrups and cough-suppression lozenges such as Robitussin. Codeine is often used too, but codeine is easily converted to undesirable drugs such as morphine and heroin in the lab.

Some people have mentioned 'psychological coughing', a cough which is triggered by psychological stressors or some other subconscious phenomenon. The surprising thing is that it's normally the other way round – if the cough is treated the psychological problems tend to fade thereafter.

Coughing is the most common symptom observed by doctors. It's good to know about the cough. The only problem really is figuring out why it is spelt this way. Etymological explanations such as this might explain the spelling, but not the pronunciation. Although the arcane exponents of consonantal shift theory might beg to explain it, they continue to beg in vain. *cough*