Toxic shock syndrome is a sudden, potentially fatal condition. It's caused by the release of poisonous substances from an overgrowth of bacteria called Staphylococcus aureus, or staph, which is found in many women's bodies. Toxic shock syndrome is still mostly a disease of menstruating women who use tampons. TSS typically starts with signs and symptoms similar to the flu, including fever (temperature 102°F), chills, headache, muscle aches, vomiting, or diarrhea. Women may also experience dizziness or lightheadedness when standing, or low blood pressure.