Diagnosis and treatment of diseases in the elderly have always been difficult for many reasons, including the atypical course of the diseases, especially in patients with cognitive impairment and the delayed symptoms manifestation. Frailty is of considerable importance, which can stand behind the listed factors and constitute both a consequence of chronic diseases and the background for newly acquired ones. The article presents three clinical cases with atypical presentation of acute abdomen due to frailty. Diagnostic algorithms and questionnaires are given that will help a practitioner identify asthenic syndrome in elderly and senile patients.