An enteric preparation having a film-forming property and acid resistance is provided by using a simple and efficient method without using a special cooling apparatus. More specifically, provided is a method for producing an aqueous enteric coating liquid including the steps of: partially neutralizing an aqueous suspension including a cellulosic enteric material with an aqueous alkali solution, and mixing the partially-neutralized aqueous suspension with a plasticizer. Also provided is a solid preparation including a core including a drug and a coating portion obtained by coating the core with the produced aqueous enteric coating liquid. Further, provided is a method for producing a solid preparation, including respective steps in the method for producing an aqueous enteric coating liquid and a step of coating a core including a drug with the produced aqueous enteric coating liquid.
