DDC warns beachgoers of ‘blue dragon’ after sighting in Phuket

DDC warns beachgoers in Phuket about the blue sea slug, or “blue dragon,” after sightings at Karon Beach, advising caution for those allergic to jellyfish venom.

The Department of Disease Control (DDC) on Thursday warned the public to exercise caution about the blue sea slug after it was spotted at a Phuket beach on Tuesday.

The DDC announced that a lifeguard at Karon Beach in Phuket had spotted a blue sea slug, commonly known as the “blue dragon,” washed ashore.

The DDC confirmed the creature was a blue sea slug, which could pose a danger to beachgoers, especially those allergic to the venom of jellyfish.DDC Director-General Panumas Yarnwetsakul explained that the blue sea slug is a carnivorous predator that feeds on other venomous floating creatures, most notably the Portuguese man o’ war. After consuming its prey, the slug stores the stinging cells (nematocysts) in the tips of its finger-like appendages, called cerata.

By concentrating these stinging cells, the blue dragon’s sting is more powerful and dangerous than that of its prey. This venom serves as its primary defense against predators and can cause a painful and potentially dangerous sting to humans who come into contact with it.Panumas advised people who touch the blue dragon to follow these steps:


Immediately leave the sea and call 1669 for emergency health services
Avoid scratching or touching the affected areas to prevent the venom from spreading
Pour household vinegar over the affected area for at least 30 seconds
Rush to the hospital if the condition does not improve.


DDC Deputy Director-General Anek Moongomklang added that tourists should protect their entire bodies with clothing before swimming in the sea and should avoid swimming immediately after it rains. He also advised tourists to be aware of warning signs regarding the presence of poisonous jellyfish or blue dragons.

(2025/08/14-00:00)