There are more causes of pain in the second toe of the left foot, and the common cases are the following: First, due to excessive exercise, strenuous sports, caused by the strain on the metatarsophalangeal joint and the ligaments around the joint, this time there will be pain in the toe. Second, it may be due to degeneration of the interphalangeal joints, forming degenerative osteoarthritis, in the cold wind, cold water stimulation, there will be pain in the toe joint. Third, in the case of valgus, the big toe tends to push the second toe to the dorsal side, which will cause a supination deformity of the second toe. In this case, the plantar focus of the foot will change, with the normal focus being below the base of the big toe. When valgus occurs, the focus shifts to the underside of the second toe, which causes pain on the bottom of the second toe.