O-shaped legs in infants may be caused by physiological factors or pathologic factors such as rickets, osteoarthritis and other causes. Depending on the cause of the disease, general treatment and drug treatment can be taken. There is no “fastest” way to straighten legs. 1. Physiological factors: may be a stage in the development of the body process, with the growth and development of infants, the general symptoms can be corrected on their own, usually do not need special treatment, it is recommended that observation. 2. Rickets: If vitamin D intake is insufficient or lack of sufficient sunlight time will lead to rickets, babies with O-shaped legs, mothers should strengthen the nutrition, to ensure enough milk, and take babies to get more sunshine; you can also use vitamin D drops, calcium gluconate tablets and other medications for the treatment of babies. 3. Osteoarthritis: Diseases that mainly damage joints and involve the whole joint tissues can lead to O-shaped legs in infants. Parents are advised to give infants more milk, soy milk, etc., or topical ketoprofen gel indomethacin spray and other drugs for treatment. Infants with symptoms of O-shaped legs, after ruling out physiological factors, should promptly consult the doctor and follow the doctor’s instructions for medication, so as not to delay the condition.