In my paper I have emphasized on a danger in the ocean that is fairly unfamiliar to most people, namely jellyfish. Because more and more people enters the oceans each year in form of different water activities, it is important for medical personnel, especially at travel clinics, to know about this potential hazard and to inform tourists about it. My objective is to capture and gather information about jellyfish species in the Indo-Pacific region that pose a threat to humans, their mechanisms of defense and to discuss the treatment of attacks. I will also provide an outline of frequency and geographical locations of encounters with these animals. By comparing articles on the subject I have tried to give a summary of the most effective ways of first aid, prevention and medical treatment of jellyfish-stingsMost reported deaths occur in the region of Northern Australia. A total of 66 fatalities have been reported since 1884 in this area. Fenner has estimated that several hundreds or up to a thousand unreported deaths occur in the Philipines each year.It seems like the most effective way of reducing fatalities due to jellyfish stings is by the means of preventive measures such as public information, patrolled beaches, protective clothing (stinger suites) and enclosed swimming areas during the stinger season. If a potential fatal stinger accident does happen it is important to get the victim out of the water, call an ambulance and start basic CPR. Only one anti-venom has so fare been developed. Vinegar has shown to have good effect on preventing venom discharge from the jellyfish tentacles when pored over the stinging lesions. Systemic symptoms should be treated in a hospital according to normal guidelines.The paper can be used as information for tourist and as a guideline for doctors who wish to inform theirs patients about potential jellyfish stings.