Here is an example of bilateral pleural effusions. Note that the fluid appears reddish, because there has been hemorrhage into the effusion. This is a serosanguinous effusion.
The milky white fluid shown here in the peritoneal cavity represents a chylous ascites. This is an uncommon fluid accumulation that can be due to blockage of lymphatic drainage, in this case by a malignant lymphoma involving the mesentery and retroperitoneum.