Periodos
Period blood: colour, clots and smell
Revisado: 4 de octubre de 2026
Solo en inglés por ahoraPeriod blood can change colour, contain small clots and have a mild smell, and this is usually normal. Here is what to expect and which changes are worth checking.
How the colour can change
Period blood is not always bright red. When your flow is heaviest, it is usually red. On lighter days it may look pink, dark red or brown. Darker red or brown blood is common at the start or end of a period, when the flow is lighter. Bright red is more common on the heaviest days. The colour can change within the same period, and this is normal.
Clots and bits of tissue
Period blood is not only blood. It also carries tissue from the womb lining as your body sheds it. So its texture can vary, and it may contain small clots or bits of tissue. Small clots can be part of a normal period. Clots larger than about 2.5 cm, the size of a large coin, can be a sign of heavy periods. So can needing to change a pad or tampon every 1 to 2 hours, or bleeding for more than 7 days.
What a normal smell is
It is normal for the vagina to have a light smell. Some people notice almost none. The smell can change a little through your cycle and may be stronger after sweating or sex. A strong, fishy or unpleasant smell is different and may point to a problem. Possible causes include an infection such as bacterial vaginosis or trichomoniasis, or a tampon that has been forgotten. You do not need to wash inside your vagina (douching). It can upset the natural balance of bacteria there.
Changes worth checking
See a doctor or nurse if you often pass clots larger than about 2.5 cm, or if your periods are very heavy or last more than 7 days. Also get checked if you notice a strong or unusual smell that does not go away. Itching, burning, soreness or an unusual discharge are also worth checking. If you think a tampon may have been left inside, get checked soon. Adding a note or a custom tag in Ciclo about colour, clots or smell can help you describe what has changed.
When to get urgent help
If you suddenly get a high fever, vomiting or a rash, or feel dizzy or faint, while using a tampon, cup or disc, take it out and get medical help straight away. If you feel very unwell or confused, or have trouble breathing, call your local emergency number. These can be signs of toxic shock syndrome, a rare but serious illness. Call your local emergency number or go to an emergency department if you are bleeding heavily and you faint or feel about to faint, or you have chest pain or trouble breathing. If heavy bleeding makes you feel dizzy, light-headed or weak, contact a doctor or nurse the same day.
This is general information, not a diagnosis. If you notice a change in your period that worries you, talk to a doctor or nurse.