Although black-colored period blood is usually nothing to worry about, it can occasionally be a sign of a more serious health condition. So, if you’re unsure what’s normal and what’s not, don’t panic. We spoke with Dr. Kimberly Fallon, MD, FACOG, PAG Certified, an OB/GYN with Holy Name Medical Center in New Jersey, about what to expect with black period blood and when it’s a good time to go to a doctor.