The present invention relates to the usage of particles which comprise metals and/or metal oxides to reduce the amount of specific compounds in vivo. More specifically, and as an example, the present invention discloses that microparticles comprising manganese oxide can reduce the amount of hydrogen sulfide (H2S) in the gastrointestinal tract of patients suffering from the presence of too much hydrogen sulfide without releasing any (potentially toxic) manganese in their intestinal tract. In other words, the present invention discloses particles which can -for example- be used to treat excess flatulence or irritable bowel syndrome and/or inflammatory bowel diseases.
