Many herbal medicinal products have been found to contain synthetic prescription drugs as chemical adulterants. This is become evident by the number of toxicity cases and adverse reactions reported in which casualties were reported via analytical techniques that detected the presence of chemical adulterants in them, which could be responsible for their toxicity. The adulteration of herbal medicinal products with synthetic drugs continues to be a serious problem for regulatory agencies. The quality control standards of various medicinal plants used in indigenous system of medicine are becoming more relevant today in view of commercialization of formulations based on medicinal plants. For standardization and quality assurance purposes, following 3 attributes are desirable i) Authenticity, ii) Purity and iii) Assay. Authenticity relates to proving that the material is true. Authentication in itself involves many parameters including gross morphology, microscopy, chemical analysis and DNA fingerprinting. Purity pertains to evaluating that there are no adulterants present in the plant material. Assay part of standardization is chemical and biological profiling which could assess the chemical effects. What is Adulteration? Adulteration is a process/practice of substituting the original drug/herb with completely or partially similar looking substance. The substance may be inferior in quality or may be therapeutically inactive. What is Deterioration? It is the process of degradation or destruction of herbs which leads to loss of therapeutic activity of the drug/herb. Deterioration & Adulteration are inter-related and deterioration is the main effect of adulteration. Adulteration is classified into 2 types: Intentional Adulteration: As the name itself indicates the intentional adulteration is the process where the substitution of drug/herb is done in full awareness this type of adulteration is commonly done by suppliers/manufacturers. Un-intentional Adulteration: This is the second type of adulteration where the substitution of drug/ herbs happens without the knowledge of manufacturer/supplier. Reasons for Intentional adulteration: 1. Due to high prices of original herb/ drugs. 2. Due to lack of availability of the drug/herbs. 3. To earn more profits by substituting the herbs by the herb of lesser price. Types of Intentional adulteration: 1. Substitution with inferior varieties. 2. Adulteration by artificially manufactured substance. 3. Usage of vegetative part of same plant. 4. Substitution with superficially similar but cheaper natural drug substance. The presence of vegetative parts of the same plant with the drug in excessive amount is also an adulteration. For example, epiphytes, such as mosses, liverworts and lichens that grow over the barks also may occur in unusual amounts with the drugs, e.g. cascara or cinchona.