Several months ago I had an operation to insert a lung drain into my chest cavity as my lung kept filling with fluid. I have been draining this fluid every other day for the last 6 months and the fluid has always been a 'mustard' colour. However, the last few times we have drained the lung the fluid starts off being 'mustard' in colour and then the fluid turns red in colour and looks like blood. Over the last few weeks the area where the drain is inserted into my chest has been hurting. I put this pain down to weight loss as I have suddenly lost nearly two stone. I have put a call into the surgeon and am waiting for her reply, but wondered if anybody else had come across this.