HEALTH / Common remedies: Liniments

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THE British spend nearly pounds 20m a year on liniments, embrocations, creams, balms, and lotions which are rubbed into the skin in the belief that this will relieve the pain of bruised, strained, or otherwise damaged muscles and joints. None of these appears in the doctors' manual of prescription drugs, the British National Formulary. Do these traditional embrocations do any good?

Rubbing something in is, in itself, soothing - mothers rub the knees of toddlers who have fallen over. Trainers dash on to the football field to rub the twisted knee of a player injured in a tackle. Giving attention to the injured child (or for that matter the footballer) has a psychological effect, and this will be greatly enhanced if the mother or trainer exudes confidence that the treatment is effective. Some of the relief comes from counter-irritation; the new messages sent along the nerves from rubbing the damaged knee help to swamp the pain sensations. Rubbing stimulates blood flow in the skin and this will help disperse the pain-inducing chemicals released by the damaged muscles.

Many of the ingredients of soothing rubs date back centuries. The best-known are extracts of the leaves and bark of trees: these include oil of wintergreen (the active ingredient of which is methyl salicylate, closely related chemically to aspirin), menthol, camphor and turpentine. Mixtures of these oils have powerful, pungent smells and are used as inhalants for coughs and colds as well as ointments. When rubbed into the skin they make it go red and feel warm, and some of the chemical ingredients are absorbed into the bloodstream. The oiliness of the mixtures makes them slow to evaporate so that they stay in contact with the skin for several hours, increasing the amount absorbed; but it is still very small.

The medical profession is, indeed, scornful of the application of drugs to the skin when the target of the treatment is the muscles. Certainly it is difficult to see how a drug can be expected to penetrate the waterproof outer layers of the skin and then pass across the layers of fat beneath the skin without being swept away in the bloodstream. Logically, drugs intended for the muscles should be given by injection. While people want to rub soothing ointments into the skin, however, the market will supply them.

Embrocations based on aromatic oils have an old-fashioned air about them which appeals to some customers, but others may prefer something that has a more modern, scientific basis. Ointments and gels (water- based ointments) are available containing drugs such as ibuprofen, one of the best- known of the class of drugs known as non-

steroidal anti-inflammatory agents, related to aspirin but said to be less upsetting to the stomach. Sprays and aerosols have hi-tech appeal, and several of these containing standard pain-relieving drugs are widely used by sportsmen. Some of these sprays combine the old and new technologies by using as their active ingredients the traditional oils such as wintergreen.

One final word of warning: all the oils used in liniments for pain relief are poisonous if swallowed. As little as one teaspoonful of oil of wintergreen may be fatal for a small child. Like all medicines, liniments should be kept in a safe cupboard.