A
cylinder of absorbent material inserted in to the
vagina to absorb
menstrual blood. Most commercially prepared tampons are made of
rayon, though some are made of less absorbant but also less
synthetic cotton.
The use of tampons is associated with Toxic Shock Syndrome, a rare but deadly condition. The exact causes are uncertain, but it is believed that because rayon is so absorbent, it dries out the vagina and leaves it prone to irritation and infection. The dioxins from the bleach used in most tampons may also be a factor, as the vagina presents a very quick route in to the bloodstream.
Tampons made of rayon are nevertheless popular, because unlike their cotton cousins and their still-more-natural cousins the menstrual sponges, they can be left in for up to 8 hours without leaking, though doctors recommend changing them more often to reduce the risk of TSS. Tampons are popular because they can't be felt once inserted and allow the wearer to go swimming or bathe without leaking blood. Still, they can cause irritation and sometimes discomfort, and are unsuitable for light flow days.
Many tampons come with an applicator, generally a cardboard or plastic tube holding the tampon, so that you needn't get blood on your fingers as you insert it. In practice, you get blood on your hands anyhow and end up with a bloody applicator that you can't flush. Almost all tampons have a string attached which is left hanging out of the entrance to the vagina to make removing the tampon easier.