Now a days, the environmental temperature and the humidity in air is very high in Bangladesh. As a result excessive sweating occurs. Body looses huge amount of water and salt and gets dehydrated. Anybody exposed to high temperature for long time can be a victim to ‘Heat Stroke’ or ‘Sun Stroke’. Heat stroke occurs due to high body temperature and dehydration. Children and older persons are more vulnerable. The symptoms are vomiting tendency or frank vomiting, excessive weakness, headache, muscle pain, elevated body temperature, lack of sweating, abnormal behavior, palpitation, breathing difficulty or unconsciousness. When anybody gets heat stroke he/she should immediately be taken in a cool place (under air cooler or fan), cloths should be removed, cool water in the body or ice pack in armpit, neck, back or groin should be applied immediately. If able to drink cold liquid should be given. It is wise to prevent heat stroke than to treat it. Two simple measures can prevent this unwanted life threatening situation- avoid prolong exposure or exercise in a very hot and humid weather and drink more and more pure liquids.