A study to describe the Chemical Content of Plant Species That Have Been Eaten by Dusky Leaf Monkey (Trachypithecus obscurus) at Taman Pd Utama, Port Dickson, Peninsular Malaysia: A Review. The purpose of this study is to understandt the species, plant part and chemical content consumed by dusky leaf monkey at study area. Observations were conducted over 20 days, during which the group of approximately 12-18 individuals was monitored. The results show that the monkeys consumed a diverse range of plant species and parts, including leaves, young leaves, fruits, and unripe fruits. The nutritional composition of the consumed plants revealed varying levels of water, protein, carbohydrates, calcium, and fiber. The high water content in some fruits, such as rambutan, may be particularly important during the dry season when water availability is limited. The presence of high carbohydrates in the diet plays a crucial role in shaping the gut microbiota of the langurs, while a diet rich in fiber enhances digestive function and stool quality. The feeding habits of the dusky leaf monkeys are strongly influenced by the availability of different food sources in their environment, highlighting the importance of environmental factors in determining dietary preferences. This study provides valuable insights into the feeding ecology of dusky leaf monkeys, contributing to a better understanding of their adaptability and resource utilization strategies.