Abstract
 Sometimes experienced doctors and nurses have an intuitive sense of alarm about an apparently stable patient, a sense which may be expressed as, for instance, ‘He/she seems seriously ill.’ However, this intuitive sense of alarm remains a rule of thumb, even though it is recognized as an important “diagnostic” indicator in clinical decision-making. In this review, we have attempted to clarify the meaning of the phrase by proposing a pathophysiologic/symptomatologic model that suggests that the sense of alarm is a premonitory sign of a homeostatic crisis characterized by acute systemic autonomic symptoms and acute sickness behavior. The model proposed here may help novices to avoid missing potentially critical diseases.