['To evaluate the efficacy of continuous low-level heat wrap therapy for the treatment of various sources of wrist pain including strain and sprain (SS), tendinosis (T), osteoarthritis (OA), and carpal tunnel syndrome (CTS).', 'Prospective, randomized, parallel, single-blind (investigator), placebo-controlled, multicenter clinical trial.', 'Two community-based research facilities.', 'Ninety-three patients (age range, 18-65 y) with wrist pain.', 'Subjects with moderate or greater wrist pain were randomized and stratified to 1 of the following treatments: efficacy evaluation (heat wrap, n=39; oral placebo, n=42) or blinding (oral acetaminophen, n=6; unheated wrap, n=6). Data were recorded over 3 days of treatment and 2 days of follow-up.', 'The primary comparison was between the heat wrap and the oral placebo group among SS/T/OA subjects for pain relief. Outcome measures included pain relief (0-5 scale), joint stiffness (101-point numeric rating scale), grip strength measured by dynamometry, and perceived pain and disability (Patient Rated Wrist Evaluation [PRWE]); subjects with CTS also completed the Symptom Severity Scale and Functional Status Scale.', 'Heat wrap therapy showed significant benefits in day 1 to 3 mean pain relief (P=.045) and increased day 3 grip strength (P=.02) versus oral placebo for the SS/T/OA group. However, joint stiffness and PRWE results were comparable between the 2 treatments. For the CTS group, heat wraps provided greater day 1 to 3/hour 0 to 8 mean pain relief (P=.001), day 1 to 3 mean joint stiffness reduction (P=.004), increased day 3 grip strength (P=.003), reduced PRWE scores (P=.0015), reduced symptom severity (P=.001), and improved functional status (P=.04). In addition, the heat wrap showed significant extended benefits through follow-up (day 5) in the CTS group.'] Is continuous low-level heat wrap therapy effective for treating wrist pain?