**6.2. Challenges of quality control**

Quality control of herbal drugs and their formulations is of vital importance in order to justifying their acceptability in modern system of medicine. A major concern facing the herbal drug market is the unavailability of the source and quality of herbal materials and their formulations [42]. Other factors such as the temperature, use of fresh plants, light exposure, nutrients, water availability, period and time of harvest, method of harvesting, drying, packing, storage and transportation of raw herbal material, etc., can critically affect the beneficial value of medicinal plants and quality. Some plant elements are heat labile and the plants containing them need to be dried at low temperatures [11].
