Many women have some type of nipple discharge or fluid when their breasts are squeezed, and its normal. Squeezing the nipple sends message to the brain and the pituitary gland responds by increasing prolactin levels, which in turn produces discharge from the nipple. The discharge can come in a variety of colors - gray, green and brown as well as white. Some women are more prone to more discharge including women on; birth control pills, certain blood pressure medications or on major tranquilizers. These medications increase prolactin levels in the body. There is also certain life periods when a person is more likely to get discharge than others: there may be more discharge at puberty and at menopause than the years in-between. The time to worry about nipple discharge is when it’s spontaneous (comes out by itself without squeezing), keeps on happening, and is only on one side. If it is clear and sticky, like an egg white, or bloody. Without being able to evaluate this including physical examination, it is difficult to say any more specifically what this could be. If you are concerned, you should have it checked out by your doctor.