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What causes spotting between periods?
There are a number of possible reasons for bleeding between periods, including hormonal changes, infections and certain medical conditions.
There are a number of possible reasons for bleeding between periods, including hormonal changes, infections and certain medical conditions.
Redheads are said to experience pain differently than other people and require higher doses of pain medications, depending on the drug used. Why?
The Brazilian wandering spider, also called the banana spider, is one of the planet's most venomous spiders.
New scientific techniques are helping us reconstruct people from the past in uncanny detail.
Reference A look at the phases of the moon, from new moon to full moon, including's tonight's lunar phase.
A buildup of dental plaque breaks down tooth enamel, leading to tooth decay, gum disease and other oral health conditions.
Having a stuffy nose often comes with pain and tenderness around your cheeks, eyes or forehead. But what do blocked sinuses look like inside your head?
Buying Guide Looking to check out macOS? Here are the best MacBooks for students you can buy right now.
Coming down with a cold or the flu can muffle your hearing, but why?
Heart murmurs are extra, unusual sounds heard during a heartbeat — but why do they happen?
After you've eaten beets, your poop and urine can take on a shocking red or pink color — but why?
The speed at which food moves through the digestive tract depends on many factors.
The prehistoric monument Stonehenge was built up to 5,000 years ago on Salisbury Plain in England, but its ultimate purpose remains a tantalizing mystery.
Several muscles could be called the "largest" in the body, depending on whether you're talking mass or surface area, but the body's smallest muscle has no competition.
Reference The four fundamental states of matter are solid, liquid, gas and plasma, but there others, such as Bose-Einstein condensates and time crystals, that are man-made.
Freckles can reappear or become darker after sun exposure and then fade in less-sunny seasons.
Solar eclipses are some of nature's most dramatic celestial performances. Here's a look at the science behind the eclipse, and when to watch the next one.
The Nobel Prize in Chemistry includes famous winners such as Marie Curie and Otto Hahn.
It's normal for you to occasionally get dizzy and for your vision to go dark when you stand up, but it can sometimes be a sign of a chronic health condition.