## 1 Introduction  
Pipering is a compound belonging to the alkaloids; it is responsible for the pungent taste of various pepper species, and has, in addition to being found in the members of the _Piperaceae_ family, been detected in several other plant species (_Rhododendron faurie_, _Vicoa indica_, _Anethum sowa_, and others) [1]. The amount of piperine is highest in _Pipper nigrum_ L, and varies from 2% to as high as 9% [2], depending on environmental factors such as climate and/or place of origin, as well as growing conditions. Black pepper (_Pipper nigrum_ L.) is the most used among the pepper species, and along with its worldwideutilization as a spice, it is known as an important medicinal plant. Its traditional use can be traced to thousands of years ago, due to its unique role in Ayurvedic medicine, where it represents one of the components of \"tricatu\" (equal proportions of black pepper, long pepper and ginger) [3]. Tricatu or its individual compounds are the base for 210 out of 370 formulations listed in the Handbook of Domestic Medicines and Common Ayurvedic Remedies. Pepper is traditionally recommended for fevers and a variety of gastrointestinal conditions, as well as for neurological and broncho-pulmonary disorders (asthma and chronic bronchitis) [3]. Traditional medicine, such as Chinese medicine, utilizes black pepper for the treatment of various pains (headaches, muscular pain), rheumat, infections such as strep throat and influenza, as well as for enhancing the blood circulation [2]. Pepper contains fibers, starch, proteins, carbohydrates, lignans, alkaloids, flavonoids, phenols, amides and essential oil. The compounds that are found in black pepper essential oil, which is present in a content of up to 3.5% in the fruits, give it a specific aroma and taste [4]. The major compounds found in this essential oil are sabinene, \(\alpha\)-pinene and \(\beta\)-pinene, \(\beta\)-caryophyllene, phellandrene, limonene, linalool, citral and others. Among other compounds, antioxidants such as beta caroten, lauric, myristic and palmitic acids, as well as piperine, are found in pepper [4]. The pungent taste of pepper and its many pharmacological properties are attributed to piperine (piperidine, C\({}_{17}\)H\({}_{19}\)NO\({}_{3}\)), one of its major alkaloids. Investigations on piperine bioactivities have reported the very high spectrum of physiological effects, including antihypertensive, antiaggregant, antioxidant, antitumor, antispasmodic, antiashmatic, antidepressant, anxiolytic, and many others [5]. Along with an array of biological activities, piperine is known for its ability to increase the bioavailability of drugs, and thus enhance their therapeutic potential [1; 6; 7]. Along with beneficial effects, piperine has, as the main ingredient of the most known spice, pepper, been traditionally used as a food for centuries, and does not present any threat upon human consumption. Additional studies have revealed the safety of its consumption by reporting a lack of piperine genotoxicity in Ames tests and in micronucle tests [8]. This review encompasses the available literature data on the various biological activities of piperine, as well as the results of clinical studies performed on humans.