To provide a sleep-related health ameliorative agent for e.g. a food/drink with no concern for side effects.

The sleep-related health ameliorative agent comprises as active ingredient a prebiotic such as an oligosaccharide or a probiotic such as Clostridium butyricum, Bacillus natto or Bacillus coagulance. A food/drink containing the prebiotic or probiotic as active ingredient and labeled with an indication to the effect that it has a sleep-ameliorative effect is also provided. It is preferable that the prebiotic be at 1 g or more per meal and the probiotic at 10 mg(about 108 as bacterial counts) per meal in terms of microbial cells.