The wall of the cyst has endometrial glands in it. As these cysts progress they frequently produce a thick dark material the consistency of fudge syrup trapped inside. If a functional cyst is found but isn't causing symptoms, it is usually just observed. Sometimes pain or long duration forces us to try to hasten its resolution. Anything that prevents ovulation or turns off estrogen and progesterone production should help.
Oral contraceptives are the most common treatment.
Ruptures may result in various experiences. They may go unnoticed or they may be associated with sudden, often intense, pain. The body naturally absorbs and removes these fluids. Even blood is generally removed without a problem, although usually more slowly than other fluids. Any cyst that does not behave like a functional cyst should be evaluated further so that serious problems like cancer can be ruled out.