For other uses, see Drug (disambiguation).
File:A small cup of coffee.JPG
Caffeine, contained in coffee and other beverages, is the most widely used psychoactive drug in the world. 90% of North American adults consume the substance on a daily basis.[1]
File:Liquor store in Breckenridge Colorado.jpg
Alcohol is a commonly consumed drug. The global alcoholic drinks industry was worth nearly $1 trillion in 2013.[2] Beer is the third-most popular drink worldwide, after water and tea.[3]
File:Papierosa 1 ubt 0069.jpeg
Cigarettes, containing nicotine, are one of the world’s most widely consumed drugs.[4]

A drug is, in the broadest of terms, a chemical substance that has known biological effects on humans or other animals.[5] Foods are generally excluded from this definition, in spite of their physiological effects on animal species.[6][7][8]

In pharmacology, a drug is "a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being."[6] Pharmaceutical drugs may be used for a limited duration, or on a regular basis for chronic disorders.[9]

Psychoactive drugs are chemical substances that affect the function of the nervous system, altering perception, mood or consciousness.[10] Alcohol, nicotine, and caffeine are the most widely consumed psychoactive drugs worldwide.[11]

Recreational drugs are drugs that are not used for medicinal purposes, but are instead used for pleasure.[12] Common recreational drugs include alcohol, nicotine and caffeine, as well as other substances such as opiates and amphetamines.

Some drugs can cause addiction and habituation [13] and all drugs can cause side effects.[14] Many drugs are illegal for recreational purposes and international treaties such as the Single Convention on Narcotic Drugs exist for the purpose of legally prohibiting certain substances.


In English, the noun "drug" is thought to originate from Old French "drogue", possibly deriving later into "droge-vate" from Middle Dutch meaning "dry barrels", referring to medicinal plants preserved in them.[15] The transitive verb "to drug" (meaning intentionally administer a substance to someone, often without their knowledge) arose later and invokes the psychoactive rather than medicinal properties of a substance.[16]


File:Nexium (esomeprazole magnesium) pills.JPG
Nexium is a proton pump inhibitor. It is used to reduce the production of stomach acid.
Main article: pharmaceutical drug

A medication or medicine is a drug taken to cure and/or ameliorate any symptoms of an illness or medical condition, or may be used as preventive medicine that has future benefits but does not treat any existing or pre-existing diseases or symptoms.

Dispensing of medication is often regulated by governments into three categories—over-the-counter (OTC) medications, which are available in pharmacies and supermarkets without special restrictions, behind-the-counter (BTC), which are dispensed by a pharmacist without needing a doctor's prescription, and prescription only medicines (POM), which must be prescribed by a licensed medical professional, usually a physician.

In the United Kingdom, BTC medicines are called pharmacy medicines which can only be sold in registered pharmacies, by or under the supervision of a pharmacist. These medications are designated by the letter P on the label.[17] The range of medicines available without a prescription varies from country to country.

Medications are typically produced by pharmaceutical companies and are often patented to give the developer exclusive rights to produce them. Those that are not patented (or with expired patents) are called generic drugs since they can be produced by other companies without restrictions or licenses from the patent holder.

Spiritual and religious use

Main article: Entheogen
File:Flowering San Pedro cactus.jpg
Flowering San Pedro, a psychotropic cactus that has been used for over 3,000 years.[18] Today the vast majority of extracted mescaline is from columnar cacti, not vulnerable peyote.[19]

The spiritual and religious use of drugs has been occurring since the dawn of our species. Drugs that are considered to have spiritual or religious use are called entheogens. Some religions are based completely on the use of certain drugs. Entheogens are mostly hallucinogens, being either psychedelics or deliriants, but some are also stimulants and sedatives.


Main article: Nootropic

Nootropics, also commonly referred to as "smart drugs", are drugs that are claimed to improve human cognitive abilities. Nootropics are used to improve memory, concentration, thought, mood, learning, and many other things. Some nootropics are now beginning to be used to treat certain diseases such as attention-deficit hyperactivity disorder, Parkinson's disease, and Alzheimer's disease. They are also commonly used to regain brain function lost during aging. Similarly, drugs such as steroids improve human physical capabilities and are sometimes used (legally or not) for this purpose, often by professional athletes.

Recreational drug use

Main article: Recreational drug use
Further information: Prohibition of drugs

Recreational drugs use is the use of a drug (legal, controlled, or illegal) with the primary intention of altering the state of consciousness through alteration of the central nervous system in order to create positive emotions and feelings.

Some national laws prohibit the use of different recreational drugs, and medicinal drugs that have the potential for recreational use are often heavily regulated. On the other hand, there are many recreational drugs that are legal in many jurisdictions and widely culturally accepted. There may be an age restriction on the consumption and purchase of legal recreational drugs. Some recreational drugs that are legal and accepted in many places include alcohol, tobacco, betel nut, and caffeine products, and in some areas of the world the legal use of drugs such as khat is common.

Administering drugs

Drugs, both medicinal and recreational, can be administered in a number of ways, or routes. Many drugs can be administered via more than one route.

  • Bolus is the administration of a medication, drug or other compound that is given to raise its concentration in blood to an effective level. The administration can be given intravenously, by intramuscular, intrathecal or subcutaneous injection.
  • Inhaled, (breathed into the lungs), as an aerosol or dry powder. (This includes smoking a substance)
  • Injected as a solution, suspension or emulsion either: intramuscular, intravenous, intraperitoneal, intraosseous.
  • Insufflation, or snorted into the nose.
  • Orally, as a liquid or solid, that is absorbed through the intestines.
  • Rectally as a suppository, that is absorbed by the rectum or colon.
  • Sublingually, diffusing into the blood through tissues under the tongue.
  • Topically, usually as a cream or ointment. A drug administered in this manner may be given to act locally or systemically.[21]
  • Vaginally as a suppository, primarily to treat vaginal infections.

See also


  1. Richard Lovett (2005-09-24). "Coffee: The demon drink?". Retrieved 2014-05-01. 
  3. Nelson, Max (2005). The Barbarian's Beverage: A History of Beer in Ancient Europe. Abingdon, Oxon: Routledge. p. 1. ISBN 0-415-31121-7. Retrieved 21 September 2010. 
  4. According to the statistic of the Food and Agriculture Organization the production quantity in 2006 of coffee was 7.8 million tonnes and of tobacco was 6.7 million tonnes.
  5. "Drug." Merriam Webster: Concise Encyclopedia
  6. 6.0 6.1 "Drug." Unabridged (v 1.1), Random House, Inc., via Retrieved on 20 September 2007.
  7. "Drug Definition". Retrieved 2014-05-01. 
  8. "Drug - Definition". Retrieved 2014-05-01. 
  9. "Drug." The American Heritage Science Dictionary, Houghton Mifflin Company, via Retrieved on 20 September 2007.
  10. "CHAPTER 1 Alcohol and Other Drugs". ISBN 0-7245-3361-3  Missing or empty |title= (help)
  12. "Recreational Drug". The Free Dictionary. Retrieved 16 March 2015. 
  13. Fox, Thomas Peter; Oliver, Govind; Ellis, Sophie Marie (2013). "The Destructive Capacity of Drug Abuse: An Overview Exploring the Harmful Potential of Drug Abuse Both to the Individual and to Society". ISRN Addiction 2013. doi:10.1155/2013/450348. Retrieved 15 April 2015. 
  14. "MHRA Side Effects of Medicines." MHRA Side Effects of Medicines,
  15. Harper, Douglas. "drug". Online Etymology Dictionary. 
  16. Tupper, K.W. (2012). Psychoactive substances and the English language: "Drugs," discourses, and public policy. Contemporary Drug Problems, 39(3), 461-492.
  17. "Glossary of MHRA terms - P". MHRA. Retrieved 2008-11-05. 
  20. Lingeman, Drugs from A-Z A Dictionary, Penguin ISBN 0-7139-0136-5
  21. "?". 

Further reading

  • Richard J. Miller: Drugged: The Science and Culture Behind Psychotropic Drugs. Oxford University Press, 2014. ISBN 978-0-19-995797-2

External links

  • DrugBank, a database of 4800 drugs and 2500 protein drug targets