Phytomedicine has been used by humans since ancient times to treat a variety of diseases. However, the use of herbal medicines faces great challenges such as poor water and lipid solubility and instability, which lead to low bioavailability and insufficient therapeutic efficacy. Recently, it has been shown that nanotechnology-based drug delivery systems are appropriate to overcome the above-mentioned limitations. The present review first discusses herbal medicines and the challenges involved in formulation of these drugs. The different types of nano-based drug delivery systems used in herbal delivery and their potential to improve therapeutic efficacy are summarized and common techniques for preparing nanocarriers used in herbal drug delivery are also discussed. Finally, a list of nanophytomedicines that have entered clinical trials since 2010, as well as those that have been approved by the FDA, is presented.