These words relate to substances, natural or synthetic, that are intended to aid in the diagnosis, prevention, treatment or cure of physical and mental disorders.

Drug is the most general, being applicable to any substance serving those purposes.

• The doctor prescribed a new drug for his patient; Many drugs have been used in the treatment of malaria.

The plural form carries an added suggestion of improper or excessive use: an addiction to drugs . Medicine and remedy are close synonyms for drug , but both may be extended to other agencies or procedures supposedly conductive to health.

• Sunshine and rest are good medicine for convalescents: The best remedy for overweight is careful dieting.

Medicament is a learned variant of medicine , seldom used nowadays. Medicinal , known chiefly as an adjective, is being increasingly used as a noun by commercial enterprises concerned with the manufacture and marketing of drugs : the export of medicinals to South-East Asia.

Biological , generally used in the plural, also has gained a foothold as a substantive. It denotes a class of drugs prepared from living animal sources and usually administered under medical supervision: serums, vaccines and hormone products may now be referred to as biological . Ethical applies to "elite" drug preparations (including medicinals and biologicals ), which in most cases are obtainable only from chemists and on prescription. Pharmaceutical describes all medical remedies made by drug firms, from the ethicals available at the chemist’s down to the proprietary lines, such as cough medicine, sold by the self-service grocery.

Narcotic , in the medical sense of the word, is a drug that has limited, often variable capacity to relive pain or induce sleep; morphine, codeine and certain other opium derivatives are narcotics . It is this power, together with a strong habit-forming tendency, that has led to their widespread abuse and given both the drug and the word a bad name: the traffic in narcotics ; narcotic addiction. Specific , as the word implies, refers to any drug or medicinal that is adapted for the treatment, alleviation or cure of some clearly identified abnormal condition.

• Digitalis is a specific for many kinds of heart disease: The best specific for the control of diabetes mellitus is insulin.

Medication has become popular as a generic term for anything that is given or administered to a patient undergoing therapy. This eliminates the possible unpleasantness of drug when it might be mistaken as applying to narcotic addiction rather than to prescribed treatment: nurses responsible for giving each patient the medication specified by his doctor; a new medication to combat drug addiction. It can apply widely from the simplest remedies, such as aspirin, to the most complex. Also, it refers less harshly to the tranquillizers and other drugs used to control the symptoms of mental disorder, where a cure is not possible or pragmatic: hospital bed-space freed by handling many of the mentally ill as out-patients who can be maintained by a programme of regular medication .