A drug is any substance other than food, which is taken to change the way the body or the mind functions.

Drugs can be described by placing them into different groups that often tell us how those drugs are used. Three broad categories are medicines, invisible drugs and illegal drugs. Example of each group are listed below.

Medical Drugs

	antibiotics (to treat various infections such as ear infection)
	pain medication (e.g., for after surgery)
	medicines for high blood pressure, arthritis, etc.
	minor pain medications for stomachache, toothache, etc.
	allergy medicines
	cold and cough medicines
	sleeping pills
	marijuana

Invisible Drugs

coffee, tea, cola drinks, chocolate, beer, wine, liquor, cigarettes, chewing tobacco, snuff

marijuana, cocaine, hallucinogens (e.g., LSD), crack

Many drugs are of great benefit to people who are ill. The drugs contained in medicines are important for maintaining or restoring health. In order to gain these benefits, however, drugs must be used properly and taken only when necessary.

When used incorrectly, all drugs can be harmful. Some drugs can cause your body to act in ways that would make it dangerous for you to do certain activities. For example, some medications cause drowsiness, and it is dangerous to drive after taking them. Drugs can be poisonous if you take too much of them. Some people are more sensitive to certain drugs; they can get sick if they use even small amounts of those drugs.