Loss of smell in nose after cold is mostly transient olfactory failure, which is related to olfactory nerve dysfunction and can be fully recovered usually about 3-5 days after recovering from cold. Cold is also known as upper respiratory tract infection, certain pathogens will invade the nasal cavity and stimulate the increase of nasal mucosal secretion, the olfactory cells may lose their function and the sense of smell may be diminished or disappeared. If there is a history of chronic rhinitis or sinusitis, the loss of smell will be more pronounced. The usual treatment period for colds is about 5-7 days, and the full recovery of the sense of smell takes about 10 days. If there is underlying rhinitis, the recovery time will be relatively longer. After a cold, you should actively take medication and pay attention to the diet, which should be light and easy to digest, less spicy and stimulating food, drink more water and keep warm. It is recommended to do more physical exercise to enhance physical fitness.