• Rate of remission as defined by the decrease in CDAI > 100 points and total CDAI < 150 by 4 weeks [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]
• Rate of response as defined by a reduction in HBI to less than 5 by 4 weeks [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]
• Rate of remission as defined by the decrease in HBI to less than 3 by 4 weeks [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]
• Time to response and/or remission including time to change in HBI, according to elements of the daily patient diary [ Time Frame: up to 4 weeks ] [ Designated as safety issue: No ]
• Increase in IBDQ to greater than 170 and the time to score above 170 [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]
• The change from baseline in the patient's general sense of disease activity as recorded in the individual daily diary [ Time Frame: up to 4 weeks ] [ Designated as safety issue: No ]
• Absence of night time stools, if they were present on entry, and time to disappearance [ Time Frame: up to 4 weeks ] [ Designated as safety issue: No ]
• Time to normalization of all other components in the diary [ Time Frame: up to 4 weeks ] [ Designated as safety issue: No ]
• Change in Hgb, ESR, CRP, platelet count, calprotectin from baseline and time to normalization [ Time Frame: 2 weeks and 4 weeks ] [ Designated as safety issue: No ]
• Change in global physician assessment of disease activity from baseline to study completion [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]

• Rate of remission as defined by the decrease in CDAI > 100 points and total CDAI < 150 by 4 weeks
• Rate of response as defined by a reduction in HBI to less than 5 by 4 weeks
• Rate of remission as defined by the decrease in HBI to less than 3 by 4 weeks
• Time to response and/or remission including time to change in HBI, according to elements of the daily patient diary
• Increase in IBDQ to greater than 170 and the time to score above 170
• The change from baseline in the patient’s general sense of disease activity as recorded in the individual daily diary
• Absence of night time stools, if they were present on entry, and time to disappearance
• Time to normalization of all other components in the diary
• Change in Hgb, ESR, CRP, platelet count, calprotectin from baseline and time to normalization
• Change in global physician assessment of disease activity from baseline to study completion

The purpose of this 4 week study is to determine whether PASER®, an approved delayed-release oral formulation of 4-aminosalicylic acid, in doses of 4 grams three times daily for 2 weeks followed by 4 grams twice daily for 2 weeks, will resolve an acute flare of ileocecal Crohn's disease.

• Drug: 4-Aminosalicylic acid
• Drug: PASER placebo granules

• Experimental: Oral granules administered as one 4 g packet three times daily for two weeks followed by one 4 g packet two times daily for two weeks
• Placebo Comparator: One packet of oral granules administered three times daily for 2 weeks followed by one packet two times daily for two weeks

Inclusion Criteria:

• Age 18-65
• Crohn's disease involving predominantly the ileum and/or cecum. The diagnosis must have been established by radiography, endoscopy and/or biopsy (at least 2 of the 3 modalities) with at least one confirmatory test having been performed no more than 36 months before entry. The diagnosis must have been confirmed by at least one gastroenterologist.
• Harvey Bradshaw Index of at least 7
• The onset of the acute flare should have been abrupt, declaring itself over 72 hours, and should have started no more than 4 weeks before study entry. Symptoms relating to the flare should not have diminished or started to improve prior to entry.
• Written informed consent

Exclusion Criteria:

• Concomitant corticosteroids, including budesonide
• Corticosteroids within the previous 2 months
• Cyclosporine, mycophenolate mofetil or experimental drugs during the last three months
• Maintenance infliximab, or infliximab or other biologics in the preceding 3 months
• Change in dose during previous 4 weeks in 5-aminosalicylate, probiotic and/or antibiotic, or in chronic azathioprine, 6-mercaptopurine, or methotrexate
• If currently using azathioprine, 6-mercaptopurine or methotrexate, these must have been used steadily for at least 4 months
• Current experimental drugs or experimental drugs within the last 3 months
• If the severity of the flare has started to decrease spontaneously
• Coexisting diagnosis of primary sclerosing cholangitis,
• Infectious diarrhea,
• Signs of intestinal obstruction or perforation or abscess,
• New fistulization as part of the acute flare or increased activity in chronic fistula(e) as part of the acute flare,
• Increased activity of pre-existing anal or rectal Crohn's disease as part of the flare
• Allergy or sensitivity to salicylates
• Pregnancy or breast-feeding
• Failure of a woman of child-bearing age to agree to use adequate contraception for the 4 week period of the trial, if sexually active
• Severe renal or hepatic disease