Trichuris suis ova therapy- 

Whipworms found in pigs ingested by humans results in short term self limited colonization of human GI tract.  Early uncontrolled studies (no placebo) found an 80% response rate of Crohns disease to this treatment (Gut. 2005 Jan;54(1):87-90.), however controlled randomized trials for the same disease found no difference between trichuris suis and placebo (Journal of Crohn's and Colitis, Volume 11, Issue 4, 1 April 2017, Pages 390–399).  Similarly, treatment of allergic rhinitis using a RCT placebo controlled trial failed to find any therapeutic effect compared to placebo, and induced diarrhea in 33% of study patients and 2% of the placebo patients (J Allergy Clin Immunol. 2010 Jan;125(1):123-30.  A RCT for ulcerative colitis found 43% of the trichuris suis group had clinical improvement and 10% went into remission  compared to 17% and 4% for the placebo controlled group (Cochrane Database Syst Rev. 2014 Jan 20;(1):CD009400).  At this time the usefulness of the therapy appears to be validated only in the use for treatment of ulcerative colitis