Phytochemicals are naturally occurring bioactive compounds that are vital to human health, nutrition, and medicine. The medicinal potential of these compounds, which include polyphenols, alkaloids, glycosides, tannins, terpenes, and saponins, in disease prevention and treatment has been extensively studied. Modern drug discovery began with phytochemicals, which have been fundamental to traditional medicinal systems such as Ayurveda, Siddha, Traditional Chinese Medicine, and ancient Egyptian and Greek pharmacology. Despite their well-documented therapeutic benefits, phytochemicals present safety concerns about toxicity, bioavailability, metabolic interactions, and herb–drug interactions. Artificial intelligence and nanotechnology, together with other developing technologies, are enhancing phytochemical research and facilitating its application in individualized therapy. Regulatory frameworks established by organizations such as the FDA, EMA, WHO, and AYUSH ensure product safety, quality, and commercialization; however, appropriate dosing and rigorous standardization remain essential to maximize efficacy and minimize adverse effects. To ensure their safe and effective use, more stringent clinical trials and improved regulatory frameworks are necessary. This chapter focuses on a thorough examination of the relevance of phytochemicals, their historical background, safety issues, dosage difficulties, regulatory factors, and future viewpoints in the field of medicine and pharmacology.