Low platelets in the elderly means that the number of platelets in the peripheral blood of the elderly is lower than the normal range, the reasons for the reduction of platelet count in the elderly are as follows: First, autoimmune diseases, the most common one is immune thrombocytopenia, which is common in the elderly patients, the reason for this is that autoantibodies against the platelets are produced, which leads to the destruction of platelets in the peripheral blood, and at the same time, such autoantibodies will also destroy the bone marrow. At the same time, this autoantibody also destroys the megakaryocytes in the bone marrow, leading to impaired maturation of the megakaryocytes, and ultimately causing a decrease in the number of platelets. After thrombocytopenia in the elderly, bleeding symptoms will appear, manifested as skin and mucous membrane bleeding spots, petechiae, internal bleeding, vomiting blood, black stools, and in severe cases, intracranial hemorrhage will be caused and lead to death. Second, blood system diseases, the most common aplastic anemia and acute leukemia, these two diseases will appear platelet reduction, easy to cause bleeding symptoms, the most serious situation is the occurrence of intracranial hemorrhage and lead to death.