Breast discharge is normal soon after giving birth and continues if a woman is breastfeeding. In other circumstances, however, release of breast milk can mean that the hormones causing milk production are out of balance. This condition is called galactorrhea. Release of a liquid other than breast milk can be a sign of infection, inflammation, or a tumor in the breast.

The pituitary, thyroid, adrenal, and ovarian glands all release hormones that govern production of breast milk. If the thyroid gland is not producing enough hormone it can lead to untimely release of breast milk. Another explanation is a benign (non-cancerous) growth on the pituitary gland. In these cases, menstruation usually stops as well. Diseases of the part of the brain that controls the pituitary gland are a third possibility. Other causes are stress, sexual stimulation, and drugs, including birth control pills, marijuana, narcotics, anesthetics, reserpine, methyldopa (Aldomet), antidepressants, and other medications prescribed for mental and emotional problems.

In many cases, no cause is found. Your doctor may order blood tests, breast x-rays, and analysis of the fluid. In some cases, a surgical procedure to remove some tissue (biopsy) may be needed to investigate the cause of discharge. If the liquid from the breast is not milk and is bloody, thin, white, green, or yellow, the cause is more likely to be a breast infection or tumor. If blood levels of a hormone that controls breast milk, called prolactin, are high, or your menstrual periods have changed, your doctor may look for a growth on the pituitary gland. An underactive thyroid can be identified through blood tests and can be treated by taking hormones in pill form. One drug, called bromocriptine, lowers prolactin production and may be helpful, although it is no longer in common use. Pituitary tumors may be removed surgically.