High alkaline phosphatase in the elderly may be caused by hyperparathyroidism, bone malignant tumor and other diseases. 1. Hyperparathyroidism: refers to excessive secretion of parathyroid hormone by parathyroid glands, which can lead to enhanced osteoclastic action, sustained excessive release of bone calcium, and increased absorption of calcium ions from the intestinal tract, thus leading to hypercalcemia and causing increased alkaline phosphatase. Generalized pain, fatigue, constipation of urinary stones, abdominal mass, elevated blood calcium and other symptoms can occur. 2. Malignant bone tumor: refers to malignant tumors occurring in bone and cartilage tissue, which can be divided into primary bone malignant tumor and metastatic bone malignant tumor. Bone destruction increases, causing elevated alkaline phosphatase value, and can cause symptoms such as pathologic bone, pain, and bony lumps. Elderly people with high alkaline phosphatase may also be caused by cirrhosis, rickets, capillary biliary hepatitis, etc. It is recommended to consult a doctor for a clear diagnosis and targeted treatment under the guidance of the doctor.