BACKGROUND: Constipation is an uncomfortable and common condition that affects many, irrespective of age. Since 1500 BC and before, health care practitioners have provided treatments and prevention strategies to patients for chronic constipation despite the significant variation in both medical and personal perceptions of the condition. OBJECTIVE: To review relevant research evidence from clinical studies investigating the efficacy and safety of commercially available pharmacological laxatives in Canada, with emphasis on studies adopting the Rome criteria for defining functional constipation. Search METHODS: PubMed, Medline, Embase and Evidence-Based Medicine Reviews databases were searched for blinded or randomized clinical trials and meta-analyses assessing the efficacy of nonstimulant and stimulant laxatives for the treatment of functional constipation. RESULTS: A total of 19 clinical studies and four meta-analyses were retrieved and abstracted regarding study design, participants, interventions and outcomes. The majority of studies focused on polyethylene glycol compared with placebo. Both nonstimulant and stimulant laxatives provided better relief of constipation symptoms than placebo according to both objective and subjective measures. Only one study compared the efficacy of a nonstimulant versus a stimulant laxative, while only two reported changes in quality of life. All studies reported minor side effects due to laxative use, regardless of treatment duration, which ranged from one week to one year. Laxatives were well tolerated by both adults and children.