The causes of pain under the toes include the following: first, toe tendinitis: due to excessive walking or weight-bearing activities, it can cause toe flexor tendons and tendon sheaths to rub against each other, which will cause tendon sheaths to proliferate and tendon inflammation to occur over time. Therefore, it will be manifested as pain below the toes, sometimes accompanied by the tendon sheath of the jamming, appearing toe activities are limited, toe popping situation. Secondly, interphalangeal joint arthritis: it usually occurs in middle-aged and old people, with the increase of age, the degeneration of articular cartilage occurs, the articular cartilage absorbs, the ability to reduce the load is gradually weakened, the articular cartilage wears out and there will be a concentration of stress between the bone and the bone, which will cause the bone to hyperplasia and deformation of the joints, and then there will be a chronic pain in the joints of the interphalangeal joints.