The present invention relates to a method of treating a liquid composition containing lacto-N-biose, the method including: preparing a liquid composition containing lacto-N-biose having a pH at 25°C of not less than 2.0 and not more than 5.5, and heating the liquid composition at a temperature of 65°C or higher. The present invention can provide a treatment method that enables thermal decomposition of lacto-N-biose to be suppressed when a liquid composition containing lacto-N-biose is heated at a temperature of 65°C or higher, a liquid preparation containing lacto-N-biose that is treated using the treatment method, a dried product produced from such a liquid preparation containing lacto-N-biose, and a method of producing a product containing lacto-N-biose.
