A drug, broadly speaking, is any chemical substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in medicine, government regulations, and colloquial usage. Medicine is the art and science of healing It encompasses a range of Health care practices evolved to maintain and restore Human Health by the This article is for the legal term For regulation of genes see Regulation of gene expression. 
In pharmacology, Dictionary.com defines a drug as "a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being. Pharmacology (from Greek grc φάρμακον pharmakon, "drug" and grc -λογία -logia) is the study of how Drugs Referencecom is an online information source that provides Encyclopedia, Dictionary, Thesaurus, and other content A chemical substance is a Material with a definite chemical composition. " Drugs may be prescribed for a limited duration, or on a regular basis for chronic disorders. In Medicine, a chronic disease is a Disease that is long-lasting or recurrent 
Recreational drugs are chemical substances that affect the central nervous system, such as opioids or hallucinogens. Recreational drug use is the use of Psychoactive drugs for Recreational purposes rather than for work, medical or spiritual purposes In Vertebrates the central nervous system ( CNS) is the part of the Nervous system which is enclosed in the Meninges. An opioid is a chemical Substance that has a Morphine -like action in the body The general group of pharmacological agents commonly known as hallucinogens can be divided into three broad categories Psychedelics, Dissociatives  They may be used for perceived beneficial effects on perception, consciousness, personality, and behavior. In Psychology and the Cognitive sciences perception is the process of attaining awareness or understanding of sensory Information. Consciousness has been defined loosely as a constellation of attributes of Mind such as Subjectivity, Self-awareness, Sentience, and the Behavior or behaviour (see spelling differences) refers to the actions or Reactions of an object or Organism, usually  Some recreational drugs can cause addiction and habituation. Drug addiction is widely considered a pathological state. The disorder of addiction involves the progression of acute Drug use to the development of drug-seeking 
Drugs are usually distinguished from endogenous biochemicals by being introduced from outside the organism. The word endogenous means "arising from within" the opposite of Exogenous. For example, insulin is a hormone that is synthesized in the body; it is called a hormone when it is synthesized by the pancreas inside the body, but if it is introduced into the body from outside, it is called a drug. Insulin is a Hormone with intensive effects on both metabolism and several other body systems (eg vascular compliance
Many natural substances such as beers, wines, and some mushrooms, blur the line between food and drugs, as when ingested they affect the functioning of both mind and body. Beer is the world's oldest and most widely consumed Alcoholic beverage and the third most popular drink overall after water and tea Wine is an Alcoholic beverage made from the fermentation of Grape juice MIND ( Moving In New Directions) (est 1975 is an alternative education high school in Montreal, Quebec, Canada. With regard to living things, a body is the integral physical material of an individual
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. Medication, also referred to as medicine, can be loosely defined as any substance intended for use in the diagnosis cure mitigation treatment or prevention of disease Illness (sometimes referred to as ill-health or ail) can be defined as a state of poor Health. Generally speaking preventive medicine is the part of Medicine engaged with preventing Disease rather than curing it
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. For the government of parliamentary systems see Executive (government. Over-the-counter (OTC drugs are medicines that may be sold without a prescription, in contrast to Prescription drugs The name "over-the-counter" Pharmacy (from the Greek φάρμακον 'pharmakon' = drug is the Health profession that links the Health sciences with the chemical sciences Pharmacists are Health professionals who practice the art and science of Pharmacy. A prescription drug is a licensed medicine that is regulated by legislation to require a prescription before it can be obtained A health care provider or health professional is an organization or person who delivers proper Health care in a systematic way professionally to any individual in A physician, medical practitioner or medical doctor who practices Medicine, and is concerned with maintaining or restoring human Health
In the UK, BTC medicines are called pharmacy medicines which can only be sold in registered pharmacies, by or under the supervision of a pharmacist. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located However, the precise distinction between OTC and prescription drugs depends on the legal jurisdiction. In Law, jurisdiction (from the Latin ius iuris meaning "law" and dicere meaning "to speak" is the practical Authority
Medications are typically produced by pharmaceutical companies and are often patented to give the developer exclusive rights to produce them, but they can also be derived from naturally occurring substance in plants called herbal medicine. A patent is a set of Exclusive rights granted by a State to an inventor or his assignee for a fixed period of time in exchange for a disclosure of an Herbalism is a traditional Medicinal or Folk medicine practice based on the use of Plants and Plant extracts Herbalism is also known as 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. A generic drug (generic drugs short generics is a drug which is produced and distributed without Patent protection
Drugs, both medicinal and recreational, can be administered in a number of ways:
Many drugs can be administered in a variety of ways.
Recreational drugs use is the use of psychoactive substances to have fun, for the experience, or to enhance an already positive experience. Recreational drug use is the use of Psychoactive drugs for Recreational purposes rather than for work, medical or spiritual purposes The prohibition of drugs through sumptuary Legislation or Religious law is a common means of attempting to control Drug use and the National laws prohibit the use of many different recreational drugs and medicinal drugs that have the potential for recreational use are heavily regulated. Many other recreational drugs on the other hand are legal, widely culturally accepted, and at the most have an age restriction on using and/or purchasing them. These include alcohol, tobacco, betel nut, and caffeine products.
The spiritual and religious use of drugs has been occurring since the dawn of our species. An entheogen, in the strictest sense is a Psychoactive substance used in a religious or shamanic (or entheogenic) context Drugs that are considered to have spiritual or religious use are called entheogens. Some religions are based completely off of the use of certain drugs. Entheogens are mostly hallucinogens, being either psychedelics or deliriants, but some are also stimulants and sedatives. The general group of pharmacological agents commonly known as hallucinogens can be divided into three broad categories Psychedelics, Dissociatives Psychedelic drugs are Psychoactive drugs whose primary action is to alter the thought processes of the brain and perception of the mind The deliriants (or Anticholinergics are a special class of acetylcholine -inhibitor Dissociatives The name comes from their primary effect of inducing Stimulant drugs are Drugs that temporarily increase alertness and awareness A sedative, or more specifically a sedative-hypnotic, is a substance that depresses the Central nervous system (CNS resulting in calmness relaxation sleepiness
Nootropics, also commonly referred to as "smart drugs", are drugs that are claimed to improve human cognitive abilities. '''Nootropics''' popularly referred to as " smart drugs " " smart nutrients " " cognitive enhancers " and " brain enhancers Nootropics are used to improve memory, concentration, thought, mood, learning, and many others 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.
Some governments define the term drug by law. In the United States, the Federal Food, Drug, and Cosmetic Act definition of "drug" includes "articles intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease in man or other animals" and "articles (other than food) intended to affect the structure or any function of the body of man or other animals. The United States Federal Food Drug and Cosmetic Act (abbreviated as FFDCA FDCA or FD&C is a set of laws passed by Congress in 1938 giving authority to the " Consistent with that definition, the U. S. separately defines narcotic drugs and controlled substances, which may include non-drugs, and explicitly excludes tobacco, caffeine and alcoholic beverages. 
From Dutch droog = "dry", referring to medicinal plants preserved by drying them.