PURPOSE: To obtain an auxiliary liquid for drinking medicines, containing an agent for protecting gastric mucous membrane and consisting essentially of water for facilitating internal use of the medicine and to obtain an auxiliary agent for drinking medicine, used by dissolving in water.

CONSTITUTION: This auxiliary liquid consisting essentially of water is obtained by adding an agent for protecting gastric mucous membrane (e.g. gastric mucin) to auxiliary liquid so as to facilitate internal use of medicines which are prone to roughen the surface of the stomach. The auxiliary liquid for drinking medicine is sealed in a volume ratio of 50-90% based on total volume into an openable hermetically sealed container to provide a container-housed auxiliary liquid for drinking medicines. A transparent or translucent wide-mouthed bottle made of glass or plastics is preferably used as the hermetically sealed container. This auxiliary agent for drinking medicines is used by dissolving it in water to be drunk when a medicine is internally taken to protect stomach of person having a weak stomach.