Medicinal plants have healing properties and are able to synthesize various chemical compounds. These chemicals (also known as phytochemical compounds) play vital roles in determining the pharmacological properties existing in certain plants. The phytochemical compounds present in plants are associated with primary and secondary constituents. Most of the time, the secondary constituents exhibit the bioactivities in plants such as antimicrobial, antioxidant, antidiabetic, antibacterial and anti-inflammatory properties. Some common medicinal plants that have been used in curing various diseases by traditional practitioners in Malaysia are Ficus deltoidea Jack, Andrographis paniculata, Curcuma longa, Clinacanthus nutans and Eurycoma longifolia Jack. This review discusses the morphology, phytochemical compounds and phytochemical properties of selected medicinal plants in Malaysia. The plants of focus have been found to possess anti-cancer and anti-diabetic effects. This review, it is hoped will enable Malaysian researchers to explore further on the potential of these plants in investigating new and novel drugs in the future.