Five people have been hospitalised after being stung by a Lion's Mane jellyfish in recent weeks.
The sting is not fatal, but pain can spread to other parts of the body as well as the affected area.
Initially, a sting may result in itching or localised pain that may radiate to other areas of the body, potentially progressing to severe pain within 20 minutes or more.
Research published by NUI Galway and UCC shows rinsing with vinegar and then applying a heat pack for 40 minutes is the best treatment.
An above average number of Lion's Mane jellyfish have been recorded close to high population areas in recent weeks.
The season for them is between June and September and they're often found in cooler water.
Jasmine Headlam, PhD and Fullbright Researcher from the Ryan Institute at NUI Galway, says: “We often see lion’s mane jellyfish on the east coast, where the water is cooler, around hotspots like the Forty Foot diving area in Dun Laoghaire and popular beaches like Bettystown, Co. Meath and Clogherhead, Co. Louth.
In the last few weeks we’ve had reports of large adult lion’s mane from the west coast in places like Salthill, Kinvara, Carna and Oranmore in Galway as well as Newquay in Clare and even Cork harbour. We urge sea swimmers and coastal visitors to report any sightings with photographs if possible to the National Biodiversity Data Centre website and the Big Jellyfish Hunt Facebook page."