The most common use of drugs is for the treatment of various illnesses. Drugs can be taken into the body in different ways. Most drugs are taken by mouth. Others can be taken into the veins or muscles by means of a needle. A few drugs can be inhaled into the lungs where they are absorbed into the bloodstream.
Some drugs bring about a change in one's emotions.
The number-one dangerous drug in the United States is alcohol. Tobacco and marijuana follow as the second and third most widespread drugs which are harmfully used. Certain drugs can make one feel very excited or very alert. These are usually called stimulants. Certain drugs can make one feel more quiet and calm.