Methods of inhibiting the virulence of a pathogen to treat a gastrointestinal spasm in a subject, without killing the pathogen, are provided. The methods can include administering an effective amount of a formulation to treat the gastrointestinal spasm, the formulation having a tannin combined with a hydroxyl radical in a pharmaceutically acceptable excipient as a binding pair, the tannin releasing in an oxidized state from the hydrogen donor after oral administration of the formulation in the subject； wherein, the composition at least inhibits a gastrointestinal spasm in the subject when compared to a second subject in a control group in which the composition was not administered.
