Safe and effective beta-lactamase dosing for microbiome protection

A method of protecting a patient's gastrointestinal microbiome, comprising administering an effective amount of a pharmaceutical composition comprising a beta-lactamase to a patient in need thereof, wherein:

• the patient is undergoing treatment or has recently undergone treatment with a beta-lactam antibiotic, optionally selected from a penicillin and a cephalosporin;
• the beta-lactamase comprises an amino acid sequence having at least 95% identity with SEQ ID NO:
• 1, and the effective amount of beta-lactamase is between about 5 and about 200 mg.