Problems with Herbal Drugs Preparations(1):-

The number of reports of patients experiencing negative health consequences caused by the use of herbal medicines has increased in recent years . Analysis and studies have revealed a variety of reasons for such problems. One of the major causes of reported adverse events is directly linked to the poor quality of herbal medicines, including raw medicinal plant materials. It has therefore been recog- nized that insufficient attention has been paid to the quality assurance and control of herbal medicines .

Quality control directly impacts the safety and efficacy of herbal medicinal products . The implementation of good agricultural and collection practises for medicinal plants is only the first step in quality assurance, on which the safety and efficacy of herbal medicinal products directly depend, and also plays an important role in the protection of natural resources of medicinal plants for sustainable use. Some reported adverse events following the use of certain herbal medicines have been associated with a variety of possible explanations, including the inadvertent use of the wrong plant species, adulteration with undeclared other medicines
and/or potent substances, contamination with undeclared toxic and/or hazardous substances, overdosage, inappropriate use by health care providers or consumers, and interactions with other medicines, resulting in adverse drug effects .

The safety and quality of raw medicinal plant materials and finished products depend on factors that may be classified as intrinsic  or extrinsic . Inadvertent contamination by microbial or chemical agents during any of the production stages can also lead to deterioration in safety and quality. Medicinal plants collected from the wild population may be contaminated by other species or plant parts through misidentification, accidental contamination, or intentional adulteration, all of which may have unsafe consequences. The collection of medicinal plants from wild populations can give rise to additional concerns related to global, regional, and/or local over-harvesting, and protection of endangered species. The impact of cultivation and collection on the environment and ecological processes, and the welfare of local communities should be considered .

It is well established that intrinsic and extrinsic factors, including species differences, organ specificity, diurnal and seasonal variation, environment, field collection and cultivation methods, contamination, substitution, adulteration, and processing and manufacturing practises greatly affect botanical quality. Intrinsically, botanicals are derived from dynamic living organisms, each of which is capable of being slightly different in its physical and chemical characters due to genetic influence.

Diurnal and seasonal variations are other intrinsic factors affecting chemical acumulation in both wild and cultivated plants. Depending on the plant, the accumulation of chemical constituents can occur at any time during the various stages of growth. In the majority of cases, maximum chemical accumulation occurs at the
time of flowering, followed by a decline beginning at the fruiting stage. The time of harvest or field collection can thus influence the quality of the final herbal product.

There are many extrinsic factors affecting the qualities of medicinal plants. It has been well established that factors such as soil, light, water, temperature, and nutrients can, and do, affect phytochemical accumulation in plants, The methods employed in field collection from the wild, as well as in commercial cultivation, harvest, post-harvest processing, shipping, and storage can also influence the physical appearance and chemical quality of botanical source materials.

Contamination by microbial and chemical agents , as well as by insect, animal, animal parts, and animal  xcreta during any of the stages of source plant material production can lead to lower quality and/or unsafe materials. Adulteration of herbal medicines with synthetic drugs represents another problem in product quality.