Patient description: A 34 year old man comes to the clinic complaining of dizziness and severe diarrhea since yesterday. He has returned from an international trip few days ago and was living in a camp in Sudan for a month. He developed abdominal pain followed by bloating and nausea as well as loose bowel movements. Soon he was having profuse watery diarrhea without odor. The stool is watery and white but the patient has no fever. Blood pressure is 95/62 lying down and drops to 75/40 standing. The skin turgor has reduced. HR is 110 and he looks ill with dry mucosa. V. cholerae was seen in dark-field microscopy of a fresh stool specimen. The lab study is as bellow: Sodium 137 meq/L Potassium 2 meq/L Chloride 94meq/L CO2 15 meq/L Fecal leukocytes None seen Fecal occult blood Negative

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Traveler's Diarrhea Patients were enrolled in the study only if they met all of the following 1. Male and female patients 18 years of age or older 2. Female and male patients of childbearing potential must have agreed to use an effective method of birth control (this method must have been approved by the investigator and may have included total abstinence from sexual intercourse) during the treatment and follow-up study periods; female patients of childbearing potential must have had a negative pregnancy test in the 72 hours before randomization; female patients who abstained totally from sexual intercourse were not required to take the pregnancy test 3. Recent travel (i.e., must be within 30 days of randomization) from an industrialized country 4. Experiencing signs or symptoms indicative of acute bacterial diarrhea (TD), defined as at least three unformed, watery or soft, stools within the 24 hours preceding randomization and the duration of illness 72 hours before randomization, and able to provide an unformed stool sample during Screening (the latter can be the third unformed stool passed by the patient within the 24 hours preceding randomization); the bacterial cause of diarrhea was confirmed by microbiology analysis of the stool sample 5. Experiencing one or more signs or symptoms of enteric infection (moderate to severe gas/flatulence, nausea, vomiting, abdominal cramps or pain, rectal tenesmus, or defecation urgency) 6. Capable of and willing to give informed consent  Patients were excluded from the study if they met any of the following 1. Fever (> 100.4F or 38C) or presence of signs and symptoms of systemic infection Note: antipyretic medication should not have been administered in the 6 hours before this assessment 2. Known or suspected infection with non-bacterial pathogen before randomization 3. Presence of diarrhea for > 72 hours duration 4. Presence of grossly bloody stool 5. Presence of moderate to severe dehydration (i.e., presence of orthostatic hypotension and/or dehydration requiring treatment with intravenous fluids) 6. History of ulcerative colitis, diarrhea-predominant irritable bowel syndrome, Crohn's disease, celiac sprue (gluten-enteropathy), chronic pancreatitis, malabsorption, or any other gastrointestinal disease associated with diarrhea. Note: lactose intolerance treated with lactase supplements or a lactose-free diet were not excluded if these regimens were maintained during the study. 7. Receiving more than two doses of an antidiarrheal medication (e.g., antimotility, absorbent, adsorbent, antisecretory, or probiotics) within 24 hours before randomization 8. Receiving one or more of the following antibiotics, which are active against gram negative bacteria TMP-SMX, fluorquinolone, azithromycin or rifaximin within 7 days before randomization 9. Females pregnant or breast feeding or not using adequate birth control 10. Known intolerance/hypersensitivity/resistance to rifamycin or rifamycin-related antibiotics or to any excipient included in the study medications 11. Patients unable or unwilling to comply with study protocol (e.g., alcoholism, mental illness, travel schedule) 12. Participation in a clinical study with another investigational drug in the 30 days prior to randomization or while participating in this study 13. Previous participation in this study