Healthy period blood ranges from bright red to dark brown, and all of those shades are normal. The color depends almost entirely on one thing: how long the blood has been exposed to oxygen before leaving your body. Texture, volume, and smell also vary throughout your cycle, and most of what you see is perfectly routine.
What Each Color Means
Think of period blood color as a timer. The faster blood moves from your uterus out of your body, the brighter red it appears. Blood that lingers inside longer reacts with oxygen (a process called oxidation) and gradually darkens. This is why you can see several different colors in a single period.
Bright red blood hasn’t had time to oxidize. It moved through your uterus and out quickly, and it’s most common during the heaviest days of your period, typically days one through three.
Dark red blood has pooled in the uterus for a bit before being shed. It’s extremely common overnight or first thing in the morning, when gravity isn’t helping things along.
Brown or dark brown blood is highly oxidized. You’ll usually notice it toward the tail end of your period, when flow is light and the remaining blood has had plenty of time to darken. It often mixes with vaginal discharge, giving it that muddy appearance.
Pink discharge is normal at the very beginning or end of a period, when a small amount of blood mixes with clear cervical fluid on its way out and gets diluted. You might also see pink spotting around ovulation for the same reason. Persistent pink spotting at other times can sometimes signal low estrogen levels, which may cause the uterine lining to shed irregularly.
Black blood sounds alarming but is usually just very old, very oxidized blood. It’s most common at the start of a period, when leftover blood from the previous cycle finally makes its way out.
Colors That Signal a Problem
Orange blood or discharge can indicate an infection such as bacterial vaginosis or trichomoniasis, especially if it’s accompanied by an unusual smell or irritation. It’s worth getting checked rather than waiting it out.
Gray discharge is a stronger warning sign. It’s often associated with bacterial vaginosis and typically comes with a fishy smell and itching. Gray tissue passed during a known or suspected pregnancy could indicate a miscarriage.
Clots, Tissue, and Texture
Period blood isn’t a uniform liquid. It’s a mix of blood, tissue from the uterine lining, and cervical mucus, so the texture changes throughout your cycle. On heavier days, it may look thick and syrupy. On lighter days, it can be thin and watery. Both are normal.
Small clots, roughly the size of a pea or a dime, are common during heavier flow. Your body releases natural anticoagulants to keep menstrual blood fluid, but when flow is heavy, the blood sometimes exits faster than those anticoagulants can work. The result is a clot. The CDC considers clots the size of a quarter or larger a sign of abnormally heavy bleeding that warrants medical evaluation.
In rare cases, you might pass a large piece of tissue shaped somewhat like a light bulb, roughly the size of a walnut or even a small lime. This is called a decidual cast, which is the uterine lining shed in one piece rather than breaking apart. It looks fleshy and pinkish-red, almost like raw meat, and is distinctly different in texture from a blood clot. It can be startling, but it’s usually a one-time event and not dangerous on its own.
How Much Blood Is Normal
The typical period produces 10 to 35 milliliters of blood total, which is roughly one to two-and-a-half tablespoons across the entire period. That’s less than most people expect. Flow over 80 milliliters (about 16 fully soaked regular pads or tampons over the whole period) is classified as very heavy menstrual bleeding.
A practical way to gauge this: if you’re soaking through a regular pad or tampon every hour for several consecutive hours, or if large clots (quarter-sized or bigger) are frequent, your flow is heavier than what’s considered typical. Heavy periods aren’t something you just have to endure. They can lead to iron deficiency over time and are very treatable.
What It Should Smell Like
Period blood has a mild metallic smell, similar to copper pennies. This comes from the iron in blood and is completely normal. The smell may be slightly stronger on heavier days.
A strong fishy odor is different. It’s the hallmark of bacterial vaginosis, an overgrowth of certain bacteria in the vagina. BV can flare during a period and produce a grayish-white discharge alongside the fishy smell, which may be especially noticeable after sex. Trichomoniasis, a sexually transmitted infection, can produce a similar fishy or musty odor. Either way, a persistent foul smell that lasts several days and doesn’t match that familiar metallic scent is worth getting evaluated.
Changes Throughout Your Period
Seeing multiple colors and textures in a single period is the norm, not the exception. A typical pattern looks something like this: light pink or brown spotting on day one as things get started, shifting to bright red and heavier flow on days two and three, then gradually darkening to deep red or brown as the flow tapers off over the final days. Some periods are three days, others are seven. Both fall within the normal range.
Your period can also change from month to month based on stress, sleep, exercise, hormonal shifts, or whether you’re using hormonal birth control. A slightly different color or heavier flow one month isn’t automatically a concern. What matters more is patterns over time: periods that are consistently getting heavier, longer, more painful, or accompanied by unusual colors or smells.