The Emergency Department at Ysbyty Gwynedd has seen an increase in patients with jellyfish stings during the recent warm weather.
Dr Jennifer Hulse, who works at the hospital, said: "The majority of jellyfish stings do not need any medical attention and can be managed by basic first aid."
Dr Hulse added: "You definitely shouldn't pee on jellyfish stings, we guarantee this will not help!"
She said people who have been stung should follow these steps:
Remove any jellyfish parts stuck to the skin, as they may continue to release stinging chemicals. You can brush them away with the edge of a credit card.
Avoid touching the sting with your hands and do not rub with towels or clothes.
Rinse thoroughly in salt water.
Soak the affected area in hot water or take a hot shower, for at least 30 minutes.
Avoid using vinegar to treat the sting.
Symptoms of jellyfish stings include burning, throbbing, itching, redness and mild swelling.
They can be treated with painkillers like paracetamol and ibuprofen, and antihistamines may help if there is itching or a rash.
None of the jellyfish species commonly found in UK waters are severely toxic, and most stings are no more serious than a nettle sting. So it’s very rare that we need to see them in the Emergency Department.