Is it this therapy?
Anitbiotic Therapy: amoxicillin 1500 mg/day, tetracycline 1500 mg/day, and metronidazole 750 mg/day
http://www.nature.com/ajg/journal/v105/n8/abs/ajg201084a.html
A few of the members on Healing Well have had great luck with this treatment but they had UC, not Crohn's.