This is a sequential dose-escalation (with up to 3 dose levels of TSO, ie, 500, 2500, and 7500 TSO), randomized (within each of 3 periods, with a ratio of 3:1 for TSO to placebo), double-blind, placebo-controlled study to evaluate the safety of a single dose of oral CNDO-201 Trichuris suis ova suspension, as compared to placebo, in patients with Crohn's Disease.

Inclusion Criteria:

1. Males or females, 18 to 55 years old.
2. Patient has confirmed diagnosis of Crohn's Disease by established criteria with a minimum disease duration of 3 months.
3. If patient is using concomitant medications, the dose/regimen is stable and remains stable for the two weeks of close observation following TSO administration. Concomitant medications may include: 1) Oral sulfasalazine, mesalazine (5-ASA), or mesalazine derivative, if receiving it for >6 weeks and if receiving the same dose for at least 4 weeks; 2) Oral prednisone up to 15 mg/day, if receiving it for >4 weeks and if receiving the same dose for at least 2 weeks; and 3) Azathioprine or 6-mercaptopurine if receiving it for >3 months and if receiving the same dose for at least 8 weeks.
4. Hemoglobin ≥ 12 g/dL at screening.
5. Normal white blood cell count and normal lymphocyte count at screening.
6. Platelet count > lower limit of normal at screening.
7. For females of childbearing potential, negative serum pregnancy test during the screening period, not breastfeeding for study duration, and willingness to use accepted forms of reliable birth control for study duration [including bilateral tubal ligation, use of oral contraceptives, double barrier methods (diaphragm with spermicidal gel or condoms with contraceptive foam), Depo-Provera®, hormonal implants, partner vasectomy, and total abstinence]. Pregnancy tests are not required (indicate "N/A") for males or females not of childbearing potential (post-menopausal with last menstrual period >1 year ago or total hysterectomy).
8. Patient must have the ability to provide informed consent.

Exclusion Criteria:

1. Patient with ulcerative colitis, indeterminate colitis, or ulcerative proctitis.
2. Bowel surgery in past 6 months.
3. Resection of more than 50 cm of the ileum.
4. Ileostomy colostomy.
5. Septic complications.
6. Patient who is hospitalized or exhibiting signs of toxicity (sepsis), has significant or multiple strictures, or impending obstruction (as evidenced by abdominal distension, severe abdominal tenderness, fever, nausea, vomiting, or tachycardia) or anticipating a need for blood transfusion for gastrointestinal bleeding or in whom surgical intervention may be imminent.
7. Patient with gastrointestinal abscess, perforation, active draining fistulae or fistulae that are considered clinically significant or perianal lesions.
8. Patient with history of colorectal cancer or colorectal dysplasia.
9. Parenteral or tube feeding.
10. Patient with evidence of infectious colitis, e.g., Clostridium difficile, Amoebiasis, Giardia lamblia or stools positive for other enteric pathogens, ova or parasites at Screening.
11. Female patient who is pregnant or breastfeeding or wishing to become pregnant during study participation or unwilling to use birth control.
12. Patient with serum creatinine ≥ 2.0 mg/dL; blood urea nitrogen >40 mg/dL; alkaline phosphatase > 250 U/L; aspartate aminotransferase (AST) or alanine aminotransferase (ALT) > 100 U/L; or total bilirubin >1.5 mg/dL.
13. Patient with white blood count <5,000 or >15,000/mm3; platelet count <150,000 per μl; or iron or vitamin B12 deficiency. Correction of lab exclusion is allowed provided that medical condition is not deemed to put patient at risk and stability of result is sustained for a minimum of 30 days.
14. Patient with active hepatitis B virus, hepatitis C virus, liver cirrhosis or portal hypertension, cytomegalovirus, Epstein Barr Virus or herpes simplex virus or is known to be human immunodeficiency virus (HIV) positive.
15. Patient with primary sclerosing cholangitis.
16. Patient with active malignancy or treatment with anticancer drugs in the past 5 years.
17. Patient received cyclosporine, anti-TNF or other immunomodulatory agents other than azathioprine/6-mercaptopurine 12 weeks prior to Screening.
18. Patient received methotrexate 4 weeks prior to Screening.
19. Patient received metronidazole 2 weeks prior to Screening.
20. Patient received non-steroidal anti-inflammatory drugs (NSAIDS) within 2 weeks before Baseline visit for more than 3 consecutive days, except acetylsalicylic acid ≤ 350 mg/d which is allowed.
21. Patient received antibiotic, antifungal or antiparasitic medication in the last 2 weeks prior to Screening and/or would potentially require this during the study treatment period.
22. Patient with history of drug or alcohol abuse within 6 months prior to Screening.
23. Patient with evidence of poor compliance with medical advice and instruction including diet or medication.
24. Patient is unable or unwilling to swallow study medication suspension.
25. Patient with a significant medical condition which puts the patient at risk for study participation and/or for any reason is considered by the Investigator to be an unsuitable candidate to receive CNDO-201 TSO or is potentially put at risk by study procedures.
26. Patients who has participated in another clinical trial within 30 days of Screening for this trial and/or any experimental treatment for this population.