For instance, few clinical trial reports are available to support the use of herbal and botanical supplements in the prevention or treatment of high blood pressure or heart disease. At a minimum, health care professionals should ask their patients about the use of herbal products and educate them on the possibility of herb-drug interactions. The active compound of a particular herb may not be known or if known may not be on the label. Furthermore, the amount of the active substance stated may not be accurate. Quality control measures vary from company to company and from product to product. Consumers should consider buying from manufacturers that have obtained Pharmacopeia standards for product purity and content reliability, thus at least ensuring some standards are followed during manufacture.