Pills are the most generally convenient and popular of all forms of medicine. They are formed from masses of a consistence sufficient to preserve the globular shape, and yet not so hard as to be of too difficult solution in the stomach and intestines. This form is especially suitable for drugs which operate in small doses, as aloes, colocynth, &c., while the disagreeable taste is always less than when the drug is given in solution. It is also useful where it is desired that the drug shall not dissolve in the stomach or upper intestines, but shall act only in the lower intestines. In such cases the pills may be coated with keratine, which is only soluble in the lower bowels. Many substances, such as vegetable extracts, may be at once formed into pills without any addition; but most substances require the addition of a material termed an excipient for converting it into a pill-mass. The excipients in most common use are bread-crumbs, hard soap, extract of liquorice, mucilage, syrup, treacle, honey, castor-oil, and conserve of roses. From the property of preserving pills for a long time in a properly soft state the most valuable excipient is the conserve of red roses; and, perhaps, next to it treacle is the most valuable excipient, as it does not undergo any change by time, but maintains a proper consistence, and preserves the properties of vegetable powders unimpaired for years. It is common to place pills in some fine powder to prevent them from adhering to each other, and to conceal their taste. For this purpose liquorice powder, wheat-flour, starch, and magnesia are generally used in Britain, and lycopodium on the Continent. Pills retain their moisture and activity far longer in small bottles than in the ordinary pasteboard boxes. The ordinary weight of a pill is five grains; if it much exceeds that weight it is too bulky to swallow conveniently if consisting of vegetable matter. It is very common to meet with patients who express their inability to take this form of medicine. If, however, they practise with a small globular mass towards which they feel no repugnance, as a pellet of bread or a currant, placing it on the back of the tongue and gulping it down with water, they will soon get over the difficulty.
To many people the taste of pills is a great deterrent, and various methods of coating the pills are resorted to for their benefit. Formerly coating with gold or silver leaf or with a little tolu resin dissolved in chloroform were the only methods; but more recently gelatine-coated, sugar-coated, and pearl-coated pills have been prepared in vast quantities and have become very popular. There is, however, always a risk of the deterioration of such pills, owing to the length of time which they may be kept before being sold. See also QUACK MEDICINES.