OBJECTIVES: To systematically review literature on the burden of illness in patients with CC and IBS subtypes. METHODS: Medline, Medline In-process, EconLit, CINAHL, Cochrane Library, and AGA abstracts were searched. Studies reporting economic and quality of life (QOL) outcomes in IBS or CC patients were included. Study designs included case control, observational studies, surveys, and retrospective analyses.  RCT and studies reporting outcomes attributable to a specific therapy were excluded. RESULTS: 882 unique studies were identified and 35 selected: 16 evaluated economic measures only, 16 humanistic measures only, and 3 economic and humanistic measures. Studies were excluded if patient populations or outcomes were not relevant.  Selected studies included a total of 63,816 patients: 1,706 IBS-C, 2,264 IBS-D, 2,892 IBS-A, 15,830 IBS sub-type unspecified, and 1,278 CC patients.  Nineteen studies assessed economic measures: 11 evaluated direct costs, 1 indirect costs, and 7 direct and indirect costs. Indirect costs generally reflected estimated work productivity loss due to IBS symptoms or healthcare-seeking behavior.  US-based estimates of direct costs per IBS patient were $1,562/year (2002 USD) to $7,547/year (year NR, published in 2000); direct costs per CC patient were $1,912/year (2002 USD) to $7,522/year (2002-2003 USD). Indirect per IBS patient costs ranged from $791/year (1998 USD) to $7,737/year (year NR, published 2005). No study assessed costs associated with IBS-C/D/A subtypes.  In studies comparing IBS patients to non-IBS controls, IBS patients had significantly lower SF-36 domain scores, notably in vitality, general health, and physical functioning. CONCLUSIONS: Our research identified a range of methods and estimates of the burden of IBS and CC.  No economic study reported recent cost estimates by IBS subtypes; only two estimated direct costs of CC.  No studies presented QOL information in CC patients; however, patients suffering from IBS had measurable burden of disease based on QOL scores.