ABSTRACT: Background: The use of complementary and alternative medicine for weight loss is becoming increasingly common worldwide. In overweight or obese patients, this practice could be harmful. Available data concerning the use of complementary therapies and products (CTPs) for weight loss in these patients in Colombia are limited. Objectives: The aims of this study were to determine the prevalence of selftreatment with CTPs in overweight or obese patients in Colombia and to explore the relationship between CTP use and demographic, anthropometric, and biochemical parameters. Methods: This randomized, cross-sectional study was conducted at a registered dieticians' office located at the Center for Nutritional Care, School of Nutrition and Dietetics, University of Antioquia, Medellin, Colombia, and at an outpatient clinic attended by a registered dietician located at the Pablo Tob6n Uribe Hospital, Medellin, Colombia. The study enrolled a random sample of overweight (body mass index [BMI], 25-30 kg/m 2) or obese (BMI, >30 kg/m 2) male and female patients aged 20 to 50 years received nutritional treatment in Colombia in 2002. Data concerning the use of weight4oss CTPs were gathered, and their possible association with demographic, anthropometric, and biochemical data was explored. Results: This randomized study comprised 94 patients (70 women, 24 men; mean [SD] age, 36.5 [9.7] years; mean [SD] BMI, 28.4 [4.2] kg/m2). Forty-nine (52.1%) patients reported self-treatment with weight-loss CTPs; 40 (42.6%) patients used complementary products, and 21 (22.3%) used complementary therapies. Among the products, inadequately identified herbal medicines (ie, absence of available information concerning the composition of the products or information could not be obtained from the patient [many of the products used were not authorized for distribution in Colombia]), folkloric or home remedies, and commercial diets were most commonly used (40.0%, 40.0%, and 27.5%, respectively). The use of CTPs was more prevalent in women compared with men (P < 0.001; odds ratio [OR] = 6.43). In women, CTP use was significantly higher in patients with a higher educational level (P = 0.008; OR = 3.82) and in those who were single (P = 0.038; OR = 2.97). The use of CTPs was also more fre quent in patients with a negative view of their current nutritional therapy (P = 0.002; OR = 6.8). Conclusions: In the small group of overweight and obese patients in this study, 52.1% used CTPs. In obese women, those with a higher educational level and/or who were single were more likely to use CTPs. Patients were also more likely to use CTPs if they had a negative view of their current nutritional therapy.COL0074661COL0000407