Pleural effusions are a frequent problem encountered in pulmonary medicine. Some common causes of pleural effusion include chest infection, heart failure, liver failure, malignancy, and autoimmune diseases such as rheumatoid arthritis, to name a few. Often drainage of this fluid is required for both diagnostic and therapeutic purposes, which is called thoracentesis. For this procedure, we use a Safe-T-Centesis kit to place a temporary catheter in the pleural space and manually drain the fluid, which can then be sent to the lab for further testing, including cell counts, glucose, pH, protein levels, cytology, and bacterial cultures. Based on these results, we can determine if the effusion is exudative or transudative, which helps guide further management. In this case, our patient has a recurrent left-sided exudative effusion of unknown cause with underlying history of colon cancer, and malignant effusion is a concern, and we performed both diagnostic and therapeutic ultrasound-guided thoracentesis.