**6.4. Need for scientific and clinical evaluation of herbal medicine**

terminal illnesses [37], such as HIV/AIDS, malaria, diabetes and sickle-cell anemia [38]. A survey conducted in the USA showed that 78% of patients living with HIV/AIDS use some form of herbal medicine. In such cases, western medicine is perceived to have failed the public [4].

The products of herbal medicine have a long history of being safe [39], however the misuse of these medicines may have side effects due to toxic constituents [29]. In some countries, toxicological assessment of herbal medicine and associated products are not employed before placing them in the market [8]. Herbal medicine of a single plant may contain hundreds of constituents and mixed products may contain numerous times that number. The time required to isolate every single active ingredient from every herb would be tremendous [22]. Moreover, these countries lack operative machinery to legalize manufacturing quality standards and practices. Thus making hazardous herbal products continually available to consumers [8]. A study related on the use of traditional eye medicine reported that it caused 26% of childhood blindness in Malawi and Nigeria, and 25% of corneal ulcer in Tanzania [4]. Pyrrolizidine alkaloids have been reported to be fatal, these are molecules within certain plants causing hepatotoxicity through a veno-occlusion illness [10]. Nausea and probably vomiting can occur with some herbs such as ephedra and echinacea. Herbs consumed as teas have been reported to cause diarrhea and hematologic, cardiac and gastrointestinal effects [40]. Herbal products from Asia have been reported to be problematic since it contains numerous contaminants. A study on the assessment of 260 Asian patent medications reported that 25% of these products contained high levels of heavy metals and 7% contained undeclared drugs, decisively and unlawfully added to produce desired effects [41].

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

Herbal remedies can be sold as supplements, for supporting, maintaining, stimulating and promoting health in many countries. These supplements require a label that defines the ingredients are intended to affect the functions within humans in line with Act 101 of 1965 and amendments (2002) [14]. The evidence on the efficacy, safety and quality of such herbal products is unknown, therefore, raising a concern on the safety of these herbal medicines [8].

**6.3. Lack of knowledge about herbal medicine within government regulations**

**6. Challenges facing the use of herbal medicine**

220 Herbal Medicine

**6.1. Safety and toxicological concerns of herbal medicine**

**6.2. Challenges of quality control**

containing them need to be dried at low temperatures [11].

The concern surrounding safety of herbal medicinal products is increasing [8]. In order to allay these concerns and achieve public reliance on herbal medicine, manufacturers, researchers and regulatory authorities must follow inclusive clinical trials and vigorous scientific methodologies to ensure the quality and safety of herbal products [41]. The safety evaluation of any herbal drug considers two important factors; the nature and significance of the adversarial effect. Toxicity screening can disclose some of the risks related to the use of herbal medicine [43]. In 1991, WHO issued guidelines for the assessment of herbal medicine which include: (i) Quality assessment: crude plant material; plant preparation; finished product. (ii) Stability: shelf life. (iii) Safety assessment: documentation of safety based on experience or toxicology studies. (iv) Assessment of efficacy: documented evidence of traditional use or activity determination (animals, human) [6].The US Food and Drug Administration (FDA), the International Conference on Harmonization (ICH) and the United States Pharmacopeia (USPC, 1994–2001) follow these guidelines to validate herbal products [1].
