1. The stinger sacs of fresh jellyfish contain venom. Fresh jellyfish bought are usually processed and pickled 3 times with salt and alum, and water is filtered to remove the toxin. After jellyfish are processed, they should be repeatedly soaked, rinsed, and the salt and alum removed before consumption. Jellyfish should be soaked in vinegar for more than 10 minutes after cleaning because Vibrio parahaemolyticus, which is abundant on the surface of jellyfish, is most sensitive to acid, which kills Vibrio parahaemolyticus attached to jellyfish and makes it safer to consume it later. 2. Fresh jellyfish contain serotonin, tetramethylamine complex, peptides, and other substances, which may cause allergic and other histamine reactions. Meanwhile, jellyfish is a seafood product that contains certain parasites and bacteria, and Vibrio parahaemolyticus attaches to its surface. If fresh jellyfish is consumed directly, it may cause food poisoning symptoms such as abdominal pain, diarrhea, nausea and vomiting and even shock. Direct consumption of fresh jellyfish by pregnant women may also lead to fetal malformation, which is not conducive to healthy fetal development.