Primary health doctors examine many sick small patients every day. Their quantity significantly increases seasonally. Medical examination for the majority of sick children allows to set the diagnosis and start adequate therapy. Severe infectious diseases usually go in a predictable way. Doctors know very well that symptoms of sicknesses appear in a defined order and have different intensity. During examination of a sick child the doctor should always evaluate its general condition and carefully check whether alarming symptoms are present or absent. Each child having a tendency to get worse general shape, growing intensity of sickness symptoms requires a decision to be sent to hospital. Knowledge about alarming symptoms in different diseases is very important. Confirming or excluding them for a patient allows to limit mistaken diagnoses and wrong therapies. It also helps to note difficult cases, surprising course of the disease and dangerous states. Special care is required when examining sick children from the youngest age group (below 5 years).