There are many causes of sickness. Too much to eat or drink can cause a bout of vomiting as can the ingestion of infected food or drink. Such attacks of sickness may be followed by diarrhoea. There really isn’t much you can do about this type of sickness except to drink large quantities of water (to replace the fluid that has been lost) and to make a mental note to avoid whatever it was you think may have caused the problem in the first place.

Anxiety or worry can cause vomiting. The phrase ‘you make me sick’ is well established in colloquial English. Gory, unpleasant sights may cause vomiting too. There isn’t much that can be done to prevent this type of vomiting since it is usually unexpected and unpredictable.

Pregnancy is another common cause of sickness. Women are most commonly affected in the first few months of their pregnancy and the sickness usually (but not always) occurs in the mornings. Avoiding fatty smells, unpalatable foods and big meals may help, but if the sickness persists then a doctor’s advice should be sought. There are pills you can buy without a prescription which will safely control the vomiting associated with pregnancy but I do not recommend pregnant women to take any medicines without medical advice.

The type of sickness that can best be helped with pills is motion sickness which is extremely common and very debilitating. Hippocrates wrote about motion sickness 2000 years ago, although he didn’t divide it into car sickness, sea sickness, train sickness and plane sickness as we do now. He probably only had to deal with sea and chariot sickness.

A good deal of research has been done on the subject, much of it during and after the Second World War when high ranking army officers were struggling to find ways to stop sea sickness among soldiers being landed on enemy beaches. Field officers had discovered that soldiers are not at their best when as they’ve just dragged themselves from the landing craft.

Even more recently doctors involved in the American space programme have been studying the problems of motion sickness as it affects astronauts. Those doctors showed that a person who is nauseated by one type of motion isn’t necessarily made ill by another. In other words a sailor who can get round the Horn without any problems at all may be dreadfully ill in an aeroplane.

Whatever the cause of the illness the symptoms usually follow a fairly reliable pattern. The patient will feel sweaty, sick and generally unwell. He’ll probably be pale, he may salivate a good deal, and yawning seems to be a common symptom. Headaches and depression may follow and some sufferers just have to lie down and forget about the world for a while.

Depending on the conditions, between 10% and 100% of the people on a ship may develop sea sickness whereas the incidence of motion sickness on trains, planes and vehicles is much lower.

It isn’t just the motion that causes the sickness. Other stimuli such as smells, noises and vibrations make things worse.

It is, incidentally, interesting that although children often suffer from motion sickness infants rarely do. Most of the children who suffer will grow out of it or will suffer less intensely.

One of the reasons for their ‘growing out of it’ is probably that they will become accustomed to the problem and they will adapt, learning how to suffer least. To help speed up that adaptation it is useful to help children by reassuring them when they feel ill and to divert their attention with a game or puzzle. The confidence which is acquired by successfully travelling without being sick will have an effect on future travelling.

Sickness sufferers can also help themselves by reclining or tilting their head back if they begin to feel ill. It’s possible to do this in most planes, trains, cars or ships these days. And it is also a help to eat wisely before travelling. It is best to eat moderate amounts of fairly bland foods.

Just about everything that can be swallowed has been tried as an antidote to travel sickness. (I’m not going to discuss here all the ‘magical’ remedies such as putting brown paper down the back of a sufferer’s shirt – except to refer you to the section on placebos and to suggest that if the remedy works then it’s a good one!) Antihistamines have been found to be effective, and are the most commonly used drugs. They do unfortunately cause drowsiness and although this doesn’t matter too much with children, it can be a disadvantage if it is the car driver who suffers from sickness.

Antihistamines which are available include cyclizine (sold as Valoid), dimenhydrinate {Dramamine and Gravol), meclozine (Ancoloxin and Sea L?gs) and promethazine {Avomine and Phenergan). Of these, promethazine is probably one of the most effective. It may also be available as Promethazine Elixir BPCand Promethazine Hydrochloride Tablets BP but you will probably have to buy the named brands. I suggest one 25 mg tablet two hours before travelling for an adult and half a tablet for a child between six and twelve years. A 5 mg dose of promethazine as elixir can be given to a younger child if necessary. The dose can be given to adult or child the evening before travelling. Promethazine can also be used as a treatment for motion sickness. One tablet taken immediately and repeated at the following bedtime should suffice.

Anticholinergic drugs can also be used. They may produce a blurring of vision and should therefore be used with great caution by drivers. Screen and Quick Kwells contain anticholinergics. Joyrides contain a smaller dose of an anticholinergic and are therefore recommended for children.

Sure Shield Adult Traveltabs contain chlorbutol, a mild sedative, which is probably less effective than the antihistamines and anticholinergics for the treatment of sea sickness.