Ginseng (pronounced /?dns/) is any one of 11 species of slow-growing perennial plants with fleshy roots, belonging to the genus Panax of the family Araliaceae. Ginseng is found only in the Northern Hemisphere, in North America and in eastern Asia (mostly Korea, northeastern China (Manchuria), Bhutan, and eastern Siberia), typically in cooler climates. Panax vietnamensis, discovered in Vietnam, is the southernmost ginseng known. This article focuses on the series Panax ginsengs, which are the adaptogenic herbs, principally Panax ginseng and P. quinquefolius. Ginseng is characterized by the presence of ginsenosides. Siberian ginseng (Eleutherococcus senticosus) is in the same family, but not genus, as true ginseng. Like ginseng, it is considered to be an adaptogenic herb. The active compounds in Siberian ginseng are eleutherosides, not ginsenosides. Instead of a fleshy root, Siberian ginseng has a woody root. The English word ginseng derives from the Chinese term renshen (simplified: ; traditional: ). Ren means "man" and shen means a kind of herb; this refers to the root's characteristic forked shape, which resembles the legs of a man. The English pronunciation derives from a southern Chinese reading, similar to Cantonese yun sum (Jyutping: jan4sam1) and the Hokkien pronunciation "jin-sim". The botanical/genus name Panax means "all-heal" in Greek, sharing the same origin as "panacea", and was applied to this genus b cause Linnaeus was aware of its wide use in Chinese medicine as a muscle relaxant. Besides P. ginseng, many other plants are also known as or mistaken for the ginseng root. The most commonly known examples are xiyangshen, also known as American ginseng ? (P. quinquefolius), Japanese ginseng ? (P. japonicus), crown prince ginseng ? (Pseudostellaria heterophylla), and Siberian ginseng ? (Eleutherococcus senticosus). Although all have the name ginseng, each plant has distinctively different functions. However, true ginseng plants belong only to the Panax genus. Ginsenosides, unique compounds of the Panax species, are under basic and clinical research to reveal their potential properties in humans. Possibly an adaptogen, ginseng remains under preliminary research for its potential properties or therapeutic effects, such as for respiratory illnesses, quality of life, influenza or fatigue in cancer patients. P. ginseng may affect cancer in animal models but this effect remains unclear. One study in laboratory animals showed possible effects of ginseng or its ginsenoside components on the central nervous system and gonadal tissues and another on penile erection. Ginseng is known to contain phytoestrogens and may affect the pituitary gland to increase the secretion of gonadotropins. Other mice studies found effects on sperm production and the estrous cycle.