Standardization is the process of prescribing a set of standards or inherent characteristics, constant parameters, definitive qualitative and quantitative values that carry an assurance of quality, efficacy, safety and reproducibility. It is the process of developing and agreeing upon technical standards. Specific standards are worked out by experimentation and observations, which would lead to the process of prescribing a set of characteristics exhibited by a particular herbal medicine. Hence standardization is an important tool in the quality control process.

Though herbal products have become increasingly popular throughout the world, one of the impediments to their acceptance is the lack of standard quality control. The herb or herbal drug preparation in its entirety is regarded as the active substance and the constituents are either of known therapeutic activity or are chemically defined substances or group of substances generally accepted to contribute substantially to the therapeutic activity of the drug.

The profile of constituents in the final product, however, has implications on its efficacy and safety. But due to the complex nature and inherent variability of constituents of plant-based drugs, and the limited availability of simple analytical techniques to identify and characterize the active constituents solely by chemical or biological means, it is difficult to establish quality control parameters.

Herbal drug manufacturers undertake quality control testing of their products based on certain preliminary parameters. This is because it is not possible to identify/quantify the presence of all/active ingredients claimed in a formulation. Assay methods so far developed are for single pure drugs at the best quantifiable in a formulation containing a limited number of other similar or non-similar constituents. Plants being constituted of innumerable complexes of closely related and unrelated groups of compounds, it is not an easy task to standardize plant drug formulations, which may even be polyherbal in composition.

A vast array of modern chemical analytical methods involving Ultraviolet/Visible (UV/VIS) spectrophotometry, thin layer chromatography (TLC), high performance liquid chromatography (HPLC), gas chromatography-mass spectroscopy (GC-MS) and a combination of these are employed for herbal drug standardization when the active constituents are known. The task of standardization is all the more perplexing where the active constituents are not known.

Currently there is a need to develop internationally recognized guidelines for quality assurance. Ensuring the purity, safety, potency and efficacy of herbal drugs being of cardinal importance, various standards of quality are being developed for herbal drug raw material and finished products. Such standards prescribed in pharmacopoeias, formularies, WHO and ESCOP monographs and herbal drug PDRs are rigidly being followed by regulatory authorities world over.