An object is to provide an interleukin production regulator which can be used for prevention, treatment or recurrence prevention of a gastrointestinal disease or an autoimmune disease accompanied by an inflammation as the main symptom, which is highly safe, and which can be administered over a long period. Another object is to provide a method for production of the interleukin production regulator. Further object is to provide a pharmaceutical composition and a food, each of which comprises the interleukin production regulator. Disclosed are: a method for producing an interleukin production regulator having both an effect of maintaining or promoting the production of interleukin-10 and an effect of maintaining or inhibiting the production of interleukin-12, comprising the step of disrupting a cell of a microorganism belonging to the genus Bifidobacterium; an interleukin production regulator produced by the method; and a pharmaceutical and a food, each comprising the interleukin production regulator.