A 15-year-old girl presented with fever and pain in her legs. A viral infection was suspected, but within 24 hours she became confused and developed meningeal signs, based on which she was diagnosed as having meningitis. Within a few hours a 6-month-old boy developed fever, a grey colour, bulging fontanel, cold hands and feet, and was groaning. He too appeared to have meningitis. It is important to recognize this serious infection in children with fever, since delay of diagnosis and treatment may result in serious complications. Recognition is difficult because of non-specific symptoms on presentation and a lack of alarm symptoms early in the course of the disease. Alarm symptoms of serious infection in children are cyanosis, rapid breathing, decreased capillary refill, petechial rash, meningeal signs, leg pain and decreased consciousness. If serious infection is uncertain in a child with fever, parents should be advised on the potential course of the disease, the alarm symptoms and the need to seek medical help in time.