To provide a method for safely generating hydrogen sulfide gas in the stomach including using a substance used as health food product and having no problem in safety; and to provide health food product and drug medicine each enabling generation of hydrogen sulfide gas in the stomach.

The method for safely generating hydrogen sulfide gas in the stomach includes making a substance made of an acid stronger than the hydrosulfuric acid and hydrogen gas-occluded hermatype calcium react with stomach acid to generate hydrogen sulfide gas in the stomach. The substance made of the acid stronger than the hydrosulfuric acid comprises a lactic acid oligomer. The substance made of the acid stronger than the hydrosulfuric acid, and the hydrogen gas-occluded hermatype coral calcium, are orally taken at the same time. The substance made of the acid stronger than the hydrosulfuric acid suitably comprises the lactic acid oligomer.