Methods and formulations for treating inflammatory bowel disease are disclosed. The methods and formulations include, but are not limited to, methods and formulations for delivering effective concentrations of 4-aminosalicylic acid and/or 5-aminosalicylic acid to affected areas of the intestine. The methods and formulations comprise modified-release elements, providing for drug delivery to the affected or desired area. Diseases and conditions treatable with the present invention include Crohn's disease and ulcerative colitis.