Can a gut antibiotic ease Chemo's stomach woes?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * PRE-REGISTRATION INCLUSION CRITERIA * Age \>= 18 years * Histological confirmation of HER2 positive breast cancer stage I-III per American Joint Committee on Cancer (AJCC) staging 8th edition * Provide written informed consent * Breast cancer patients who will be receiving pertuzumab-based chemotherapy with either TCHP (docetaxel, carboplatin, trastuzumab, and pertuzumab) or docetaxel/paclitaxel, trastuzumab, and pertuzumab * Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0, 1, or 2 * Hemoglobin \>= 10.0 g/dL (obtained =\< 30 days prior to pre-registration) * Absolute neutrophil count (ANC) \>= 1.5 x 10\^9/L (obtained =\< 30 days prior to pre-registration) * Platelet count \>= 100 x 10\^9/L (obtained =\< 30 days prior to pre-registration) * Total bilirubin =\< 1.5 x ULN (institutional upper limit of normal) (obtained =\< 30 days prior to pre-registration) * Aspartate aminotransferase (AST) (serum glutamic-oxaloacetic transaminase \[SGOT\])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase \[SGPT\]) =\< 2.5 x ULN (obtained =\< 30 days prior to pre-registration) * Serum or plasma creatinine =\< 1.5 x ULN (obtained =\< 30 days prior to pre-registration) * Calculated creatinine clearance \>= 45 ml/min using the Cockcroft-Gault formula (obtained =\< 30 days prior to pre-registration) * Negative serum pregnancy test done =\< 30 days prior to pre-registration, for person of childbearing potential only * Willingness to return to enrolling institution for follow-up (during the active monitoring phase of the study) * Willingness to provide mandatory stool specimen for correlative research * Ability to complete questionnaire(s) by themselves or with assistance * REGISTRATION INCLUSION CRITERIA * Received pertuzumab based regimens in the adjuvant or neoadjuvant setting * Hemoglobin \>= 8.0 g/dL (obtained =\< 14 days prior to registration) * Absolute neutrophil count (ANC) \>= 1.5 x 10\^9/L (obtained =\< 14 days prior to registration) * Platelet count \>= 100 x 10\^9/L (obtained =\< 14 days prior to registration) * Total bilirubin =\< 1.5 x ULN (institutional upper limit of normal) (obtained =\< 14 days prior to registration) * AST (SGOT)/ALT (SGPT) =\< 2.5 x ULN (obtained =\< 14 days prior to registration) * Serum or plasma creatinine =\< 1.5 x ULN (obtained =\< 14 days prior to registration) * Calculated creatinine clearance \>= 45 ml/min using the Cockcroft-Gault formula (obtained =\< 14 days prior to registration) Exclusion Criteria: * PRE-REGISTRATION EXCLUSION CRITERIA * History of myocardial infarction =\< 6 months prior to pre-registration, or congestive heart failure requiring use of ongoing maintenance therapy for life-threatening ventricular arrhythmias * Failure to recover from acute, reversible effects of prior therapy regardless of interval since last treatment * EXCEPTION: Grade 1 peripheral (sensory) neuropathy that has been stable for at least 3 months since completion of prior treatment * Uncontrolled intercurrent non-cardiac illness including, but not limited to: * Ongoing or active infection * Psychiatric illness/social situations * Dyspnea at rest due to complications of advanced malignancy or other disease that requires continuous oxygen therapy * Any other conditions that would limit compliance with study requirements * Immunocompromised patients and patients known to be human immunodeficiency virus (HIV) positive and currently receiving antiretroviral therapy * NOTE: Patients known to be HIV positive, but without clinical evidence of an immunocompromised state, are eligible for this trial * Receiving any other investigational agent which would be considered as a treatment for the primary neoplasm (adjust to protocol if applicable) * Any of the following because this study involves an agent whose genotoxic, mutagenic and teratogenic effects on the developing fetus and newborn are unknown * Pregnant women * Nursing women * Women of childbearing potential who are unwilling to employ adequate contraception * Current colostomy or ileostomy * History of inflammatory bowel disease * History of irritable bowel syndrome * History of arteriovenous malformations * History of gastrointestinal bleeds * Previous surgical resection of the small bowel or colon * Previous allergy to rifaximin or its derivatives