Jellyfish are found in the sea and have see-through bodies with protruding tentacles. The tentacles have stinging cells that can hurt and sometimes cause serious harm, should you come into contact with them [source: Medline]. The tentacles of jellyfish contain poison that is released through barbs, called nematocysts, when the tentacles touch something. Jellyfish usually use the poison to capture their prey. When the tentacles come into contact with a human the poison is released and causes pain. Some of the symptoms of jellyfish sting are burning pain, itching, blisters, red marks and numbness. In more severe cases it can cause nausea and vomiting. Most jellyfish stings get better with home remedy treatment, but there are those that are more dangerous and require medical treatment [source: Mayo Clinic]. Prevention is the best remedy. Don't enter the water if you see jellyfish in the water. However, if you didn't see any jelly fish, but ended up getting stung, here's what to do:

  1. Get out of the water immediately.
  2. Do not thrash around. If you thrash around, the jellyfish may wrap its tentacles around you.
  3. Pick any tentacles you can see off your body with a towel or with the corner of a credit card. Don't rub the area.
  4. Apply vinegar liberally. This will stop any remaining nematocysts from releasing any more poison. If you do not have vinegar handy, rinse the area with salt water.
  5. Place an ice pack on the affected area. This will help relieve the pain.
  6. Get immediate medical attention should you experience dizziness or breathing difficulties [source: Cohen].