The color of your period blood reflects how quickly it’s leaving your body and how long it’s been exposed to oxygen. Bright red means fresh, fast-moving blood. Darker shades mean slower flow. Most color variations are completely normal and shift throughout a single period, but a few colors, particularly orange and grey, can signal something that needs attention.
Bright Red Blood
Bright red is what you’ll typically see during the heaviest days of your period, usually days two and three. It means blood is moving through your uterus and out of your body quickly, before it has time to react with oxygen. Your uterus actively contracts during your period, tightening and releasing to push blood out. When those contractions are strong and flow is steady, the blood stays bright red.
If your entire period is bright red from start to finish, that’s not a concern on its own. It simply means your flow stayed consistent. Some people notice bright red blood only in the middle of their period, bookended by darker shades at the beginning and end.
Dark Red and Brown Blood
Dark red blood is still normal. It just means the blood is flowing a bit more slowly, giving it more time to oxidize (react with air) before it leaves your body. You’ll often notice this shift toward the end of your period as flow tapers off.
Brown blood is simply old blood that’s had even more time to oxidize. It’s common in the first day or two of your period, when your body is clearing out leftover lining from the previous cycle, and again in the final days as things wind down. Brown spotting between periods can also happen, especially if you’re on hormonal birth control.
Black Blood
Black period blood looks alarming but follows the same logic as brown blood. It’s blood that sat in your uterus or vaginal canal long enough to fully oxidize, turning from dark brown to near-black. This is most common at the very start or very tail end of a period when flow is minimal. It sometimes has a thicker, almost paste-like consistency. On its own, black blood is not a sign of a problem.
Pink Blood
Pink period blood happens when menstrual blood mixes with cervical fluid, diluting the red color. You might see it at the very beginning of your period when flow is just starting, or during lighter days. It can also show up as mid-cycle spotting around ovulation.
Pink spotting has another possible meaning: implantation bleeding. When a fertilized egg attaches to the uterine lining, it can cause very light bleeding that’s pink or light brown. Implantation bleeding is much lighter than a period. It resembles the flow of normal vaginal discharge more than menstrual blood, and it shouldn’t soak through a pad or produce clots. If you’re seeing pink spotting around the time you’d expect your period and it stays unusually light, a pregnancy test is worth considering.
Orange Blood
Orange discharge or orange-tinged period blood is the first color on this list that may point to something medical. It can happen when menstrual blood mixes with cervical fluid, creating an orange hue. But orange discharge is also associated with bacterial vaginosis and trichomoniasis, a sexually transmitted infection. Both conditions are treatable with antibiotics.
If orange discharge comes with a strong or unusual smell, itching, or irritation, those are signs of infection rather than normal color variation.
Grey Discharge or Tissue
Grey is the one color that always warrants attention. Grey vaginal discharge can indicate bacterial vaginosis, especially if it has a fishy smell. But grey tissue mixed with bleeding has a more specific meaning: it can be a sign of miscarriage. In very early pregnancy (the first month), the embryo is only the size of a grain of rice, so it may not be visible. But you may pass blood clots containing small amounts of white or grey tissue.
If you’re passing grey tissue and there’s any chance you could be pregnant, contact a healthcare provider promptly.
Blood Clots During Your Period
Small clots during heavier flow days are normal. Your body releases anticoagulants to keep menstrual blood liquid, but when flow is heavy, blood sometimes exits faster than those anticoagulants can work, forming clots. These are typically small, dark red or almost black, and jelly-like in texture.
Size matters here. The CDC considers clots the size of a quarter (about 2.5 cm across) or larger a sign of heavy menstrual bleeding that deserves medical evaluation. Consistently large clots, especially paired with soaking through a pad or tampon every one to two hours, suggest your bleeding is heavier than normal.
How Birth Control Changes Your Bleeding
If you’re on hormonal birth control, the bleeding you get during your placebo week isn’t technically a period. It’s withdrawal bleeding, triggered by the temporary drop in hormones. Because hormonal contraceptives prevent your uterine lining from thickening the way it normally would, withdrawal bleeding tends to be lighter, shorter, and often darker in color than a natural period. Brown or dark red spotting instead of a full red flow is common and expected.
Some people on hormonal birth control also experience breakthrough spotting between periods, which is usually pink or light brown. This is more common in the first few months after starting a new method.
What the Color Pattern Looks Like
A typical period moves through a predictable color arc. It often starts brown or dark red as old blood clears out, shifts to bright red during peak flow in the middle, and fades back to dark red or brown as flow slows down. Not everyone follows this exact pattern, and that’s fine. Some people skip the brown phase entirely and start bright red. Others see mostly dark blood throughout. Cycle-to-cycle variation is also normal.
The colors worth paying attention to are orange (especially with odor or irritation), grey (especially with tissue), and any bleeding heavy enough to soak through protection every hour or two. Everything else on the red-to-brown-to-black spectrum is your body doing exactly what it’s supposed to do, just at different speeds.