Plants have been used extensively in both pharmaceutical and food industries, with consumers showing increasing interests in these products. Phytomedicines exploit a pool of biogenic resources produced by plants. However, the quality and quantity of these chemical metabolites in plants are influenced by a multitude of factors, chief among them, environmental. This review provides an overview of plant-produced chemical compounds with medicinal properties and how their production is affected by different environmental factors. An insight into how these factors can be manipulated within the plants' growing environments as a way of ensuring quality is also discussed.