The rare but serious medical condition associated with tampon use is called toxic shock syndrome (TSS). TSS is a potentially life-threatening condition that is caused by the release of toxins produced by certain bacteria, such as Staphylococcus aureus or Streptococcus pyogenes. These bacteria can grow in the when a tampon is left in for too long or if high-absorbency tampons are used. The toxins can enter the bloodstream and cause a variety of symptoms, including high fever, low blood pressure, rash, and organ failure. If you suspect you may have TSS, it is important to remove your tampon immediately and seek medical attention.