celulites, and blood borne diseases.It is a parasurgical procedure which can be done in children, delicate people, ladies, and in those who are afraid of surgery.Hirudomedicinalis(European Medicinal Leech) is the most frequently used species of leech that is not native to the Indian subcontinent. In India the species used traditionally for therapeutic purposes is Hirudinariagranulosa. Besides these, Macrobdelladecora (American medicinal leech), Hirudomichaelseni, Hirudonipponia, Hirudo verbena, and Hirudoorientalisare also being used for therapeutic purposes. Scientific research reveals that the beneficial effect of leeching occurs via blood decongestion and injection of a cocktail of several medicinally useful bioactive molecules present in their saliva.This article elaborates the indications, contraindications, types of leeches in a very candid way, and throws light on the review of various salivary gland secretions in its pharmacological action point of view after reviewing certain articles on this subject. Keywords: Leech Therapy,Salivary gland secretions, leeching, Jaloukavacharana, raktamokshana I. INTRODUCTION Leech therapy is becoming increasingly popular among practitioners of Ayurveda, which is also called as complementary and alternative medicine. Many studies are currently under way to evaluate its various medicinal effects, all around the globe and thousands of patients have been healed using leech therapy.Many traditional medical systems, for example, the Greek, Arab, and Russian, mention leech usage.[1] The origins of traditional Indian medicine ie, Ayurveda,is said to date back some 3000 years. Leech therapy has been an active part of traditional Ayurvedic medicine throughout its history.AcharyaSushruta has described Leech as Jalouka in the area of para surgical toolsie,Anushastra,which means the tool which can be used in the absence of surgical instruments.{2}The word ‗leech‘ is supposed to be derived from an old English word for physician, laece {3]. According to Sushruta, the leech is called as ‗jalouka‘ or ‗Jalayuka‘meaning that which dwells in ‗jala‘ or water [4].Leech is a freshwater amphibious worm, usually black or brown and about 10 cm in length. With a very simple etymology and a very tiny appearance,this soft slimy parasite hails in more than 650 known species in the Hirudo genus, and the most often used is Hirudomedicinalis in medical therapy [5]. Leeches were named Hirudomedicinalis by Linnaes in 1758 [6].During the seventeenth and eighteenth centuries, leech therapy played a pivotal role in therapeutic practices, which involved bloodletting and purification, a practice employed to treat many ailments, from gout to headaches [7].In India the species used traditionally for therapeutic purposes is Hirudinariagranulosa. Besides these, Macrobdelladecora (American medicinal leech), Hirudomichaelseni, Hirudonipponia, Hirudo verbena, and Hirudoorientalis[8]are also being used for therapeutic purposes. ‗Attaividal‘(leech therapy) is one of the way of bloodletting which comes under the external therapies of Siddha. Leeches have been used for therapeutic purposes before 2000 years by ancient renowned ‗Siddhars’which state that speckled leech has many active compounds in their saliva. Thus, remove toxins and impure blood and cures many diseases efficiently [9]. Leeches play a major role in Unani medicine as one of the most importantregimental therapy as ‗Irsale-Alaq‖.EminentUnani physicians have described and practiced the use of non- poisonous (medicnal) leeches in An Interdisciplinary Critical Review of Leech Therapy; Evolution, Indications, Salivary Glan…. 11 a number of diseases like joint diseases, chronic non healing ulcers,and various skin disorders like eczema, psoriasis etc.{10} The US FDA has approved medicinal leeches for commercial marketing, not as drugs, but as medical devices. According to FDA, the agency announced that leeches meet the definition of a device because they are considered to be articles intended to diagnose, cure, treat, prevent, or mitigate a disease or condition, or to affect a function or structure of the body,that do not achieve their primary effect through a chemical action and are not