In this topic you will learn about the effects of drugs on the body.

A medicine is a drug used to treat, cure, or prevent disease or injury. Medicines can be classified into two groups, based on how they are obtained. One group is made up of the over-the-counter medicines. These medicines may be purchased off the shelves in a pharmacy. They are used to treat illnesses or problems that are not very serious. Examples are cough medicines or pain relievers.

The other group is made up of medicines that can only be purchased with a written order, called a prescription, from a doctor. A prescription medicine can only be purchased in a drug store or pharmacy.

To use medicine safely, you must understand the risks and follow some basic rules. One risk is that almost all medicines have side effects. A side effect is an unwanted effect of using a medicine. Feeling dizzy or sleepy may be a side effect. Another risk is allergy. An allergy is a sensitivity to a substance. Some allergies result in a rash or fever. A third risk is dependence. Dependence is a strong need or desire for a medicine or drug. Some people may feel that they cannot do without a medicine.

Cocaine is an illegal stimulant made from the leaves of the coca plant. It is usually available as a powder, which is breathed in through the nose. Crack is a very harmful form of cocaine. People who use cocaine may become nervous, suspicious, and depressed. Heavy use also causes heart failure, seizures, brain damage, and even death.

Marijuana is an illegal mind-altering drug made from the leaves, flowers, and seeds of the cannabis plant. Some effects of smoking marijuana are increased heart rate, memory problems, nervousness, and being unable to concentrate or react quickly.

Taking more or less of a medicine than you should or using someone else's medicine can hurt you. To do this is to misuse a drug. This means using a legal drug improperly or in an unsafe way. To abuse drugs is to use legal drugs in an unsafe way or to use illegal drugs.

Knowing the effects and the proper use of legal drugs can help keep people healthy. Also, knowing the effects that drug abuse has on the body can help you make the choice not to abuse drugs and to stay healthy.