The use of medicinal herbs for medicinal purposes is an ancient practice that dates back centuries. Herbal medicine is based on the practice of using plants and plant extracts to support health and treat diseases and conditions. Traditional herbal medicines are still widely used today in many parts of the world, particularly in developing countries. The use of medicinal herbs for their pharmacological activities has been an integral part of traditional medicine and herbal remedies. Over the years, a variety of herbal remedies have been developed to treat various disease states. Compounds obtained from medicinal herbs have pharmacological activities such as antimicrobial, anti-inflammatory, antifungal, antihypertensive, and antioxidant properties. The active compounds present in medicinal herbs are mainly composed of secondary metabolites such as terpenes, alkaloids, glycosides, phenols, flavonoids, and polysaccharides. The pharmacological activities of these compounds are depending on their chemical structures, biologic sources, and therapy doses. The pharmacological activities of medicinal herbs include anti-hyperglycemic, anti-inflammatory, anti-microbial, anti-cancer, anti-diabetics, anti-allergic, digestive stimulants, and sedatives. Herbs used for medicinal purposes should be used with caution. Different herbs often interact differently and their combined effects can be unpredictable. When used therapeutically, herbal remedies can act as a form of complementary and alternative medicine (CAM). Advice from a healthcare professional should be sought before engaging in herbal therapy. Researchers are striving to understand the chemistry of medicinal herbs so that their use can become more evidence-based. Regardless of the direction of research, the therapeutic use of medicinal herbs continues to be an important part of traditional medical systems.