If the toenails of the big toe become uneven, it is usually due to the following factors: First, the most common factor is a lack of vitamins in the body, such as vitamin B and vitamin C, which leads to a poor nutritional status of the toenails, which can lead to unevenness. Secondly, a lack of trace elements, such as zinc, will also lead to the above symptoms and will result in uneven toenails. Thirdly, if the bunion is infected for a long time, such as in the case of gray nail disease or fungal infection, the nutritional status of the nail will be extremely poor and the nail will be uneven. Fourthly, after the nail is infected, especially in the big toenail, it is particularly susceptible to bacterial infections that can lead to nail infections, which can also lead to uneven nails.