Period blood can range from bright red to dark red, brown, and even black, and all of these colors are normal. The color depends almost entirely on one thing: how long the blood has been exposed to oxygen before leaving your body. Blood that flows out quickly stays bright red, while blood that lingers in the uterus oxidizes and darkens over time. Most people see several different colors within a single period, which is completely expected.
Bright Red Blood
Bright red is what most people picture when they think of period blood, and it typically shows up during the heaviest days of your flow. This color means the blood moved through the uterus and out of the vagina quickly, without sitting long enough to react with oxygen. For many people, days two and three of a period are the heaviest, so that’s when bright red blood is most common. If you notice bright red blood between periods or a flow that stays heavy for more than seven days, that’s worth paying attention to.
Dark Red and Brown Blood
Dark red blood has pooled in the uterus for a bit before making its way out. It’s had more time to oxidize, which deepens the color. You might see dark red blood overnight (when gravity isn’t helping things move along) or on days when your flow is lighter.
Brown blood is simply more oxidized than dark red. It’s extremely common at the tail end of a period, when the uterus is passing the last of its lining. By those final days, whatever blood remains has been sitting long enough to turn dark brown. Some people also notice brown spotting a day or two before their period officially starts, as small amounts of old blood work their way out. Neither dark red nor brown blood signals a problem on its own.
Black Blood
Black period blood can look alarming, but the explanation is the same as brown blood, just taken further. It’s old blood that lingered in the uterus long enough to oxidize completely, progressing from dark red to brown to black. This is most likely during low-flow days at the very beginning or end of a period. As long as there’s no unusual smell, itching, or pain, black blood is a normal variation.
Pink Blood
Pink period blood happens when menstrual blood mixes with cervical fluid, diluting its color. This often shows up at the start of a period when flow is just beginning, or at the very end. Pink spotting can also occur mid-cycle around ovulation. If you’re sexually active and notice light pink or brown spotting that lasts only a day or two and never soaks through a pad, it could be implantation bleeding, an early sign of pregnancy. Implantation bleeding looks more like vaginal discharge than a real period: it’s light, short-lived, and doesn’t contain clots.
Colors That Can Signal a Problem
While the red-to-brown-to-black spectrum is normal, a few colors fall outside the expected range.
- Gray discharge mixed with menstrual blood can be a sign of bacterial vaginosis, a common vaginal infection. It often comes with a fishy smell.
- Green or yellow discharge during your period may indicate trichomoniasis or another infection, especially if it appears bubbly or frothy.
- Orange-tinged blood can sometimes result from menstrual blood mixing with cervical fluid, but when it’s paired with a bad smell, itching, or irritation, it may also point to infection.
The color alone isn’t always enough to diagnose an issue. What matters is the combination: unusual color plus a foul or fishy odor, itching, swelling, pelvic pain, or pain during urination. Those combinations are the clearest signals that something beyond normal menstruation is happening.
Clots and Texture
Small clots during your period are normal, especially on heavier days. They form when blood pools in the uterus or vagina before being passed. Clots that are small, dark red or maroon, and jelly-like in texture are typical. The threshold worth noting: clots the size of a quarter (roughly 2.5 centimeters) or larger may indicate heavy menstrual bleeding, according to the CDC. If you’re regularly passing large clots, soaking through a pad or tampon every hour for several consecutive hours, or bleeding for more than seven days, those are signs of abnormally heavy periods that deserve evaluation.
How Color Changes Throughout Your Period
A typical period follows a fairly predictable color pattern, though everyone’s cycle is slightly different. The first day or two might bring brown or dark red spotting as the uterus begins to shed its lining. As flow picks up, blood turns bright red. Mid-period, when flow is heaviest, bright red dominates, sometimes with small clots. As flow tapers off over the final days, blood darkens again to brown or even black as the remaining lining exits slowly. Seeing this full range of colors across a single period is one of the most reliable signs that things are working as expected.
Hormonal birth control, stress, exercise levels, and hydration can all subtly shift the timing and heaviness of your flow, which in turn affects what colors you see. A lighter-than-usual period might be mostly brown, while a heavier one might stay bright red for several days. These variations from cycle to cycle are normal as long as the overall pattern stays within your usual range.