Some time ago, I was impressed by two patients who had “celiac pleural effusion” after surgery. As I mentioned in my previous article, for patients who have just undergone radical lung cancer surgery, doctors recommend a low-fat, light diet after surgery, which is more conducive to reducing pleural effusion and accelerating postoperative recovery. In our daily clinical work, we also pay great attention to educating patients. These two patients also followed our advice and did not eat meat with high fat content after surgery, so why did they still have this celiac pleural fluid? We made more detailed inquiries and found that one of the patients had eaten a lot of sunflower seeds postoperatively and the other had a penchant for sesame seed paste. Now we found the “culprit” of celiac pleural fluid. As you can see, it’s not just meat with a high fat content that can cause post-operative celiac pleural fluid, but also foods like sunflower seeds and sesame seeds that contain more plant-based fatty acids, which can also cause the symptoms. Postoperative celiac pleural fluid is not harmful in itself, but its color resembles “milk”, which can cause unnecessary panic to patients and their families, and secondly, the increase in the amount of pleural fluid can also delay the removal of chest tubes and lead to a longer hospital stay. Through the experience of these two patients, we have strengthened the dietary guidance for postoperative lung cancer patients and made more detailed preaching. If the patient’s family is still unable to determine which foods are suitable for the patient to eat, there is a simple criterion to follow, namely, if the food does not leave obvious oil stains on the clothing when spilled, it can be given to the patient. It is also important to emphasize that many patients and their families are concerned about whether eating a light diet for a long time will cause malnutrition. However, it is still more in line with health requirements to avoid large amounts of high-fat foods.