A rapid, simple questionnaire to assess gastrointestinal symptoms after oral ferrous sulphate supplementation.

Background: Oral iron supplementation is often associated with rapid onset of gastrointestinal side-effects. The aim of this study was to develop and trial a short, simple questionnaire to capture these early side-effects and to determine which symptoms are more discriminating.

Methods: The study was a double-blind placebo-controlled randomized parallel trial with one week treatment followed by one week wash-out.