Topical menthol gels are classified 'topical analgesics' and are used to relieve pain of the musculoskeletal system. However, double-blind randomized controlled trials are lacking. Here the investigators examine - in a double-blind randomized controlled cross-over trial - the acute effect of topical menthol (Biofreeze) and placebo (gel with a menthol scent) on pain symptoms in slaughterhouse workers with symptoms of Carpal Tunnel Syndrome.