Introduction: Dietary herbal products taken together with prescription medicines may have harmful effects. In this study, we evaluated the use of dietary herbal supplements and identified factors that predict the concomitant use of these supplements in patients taking drugs prescribed for chronic cardiovascular diseases. Methods: We performed a cross-sectional study with 343 patients with cardiovascular diseases. Data regarding the sociodemographic status, medical condition, number of prescription drugs, and use of herbal supplements were collected using a self-administered questionnaire. Results: Regular use of dietary herbal supplements was reported by 82.5% of patients. The most commonly consumed herbal supplement was garlic (71.2%), followed by onion (67.1%), and walnut (63.6%). Consumption of herbal supplements was commonly observed in patients with hypertension (53.6%). Among the patients in the study, 21.3% patients reported consumption of herbal supplements to the physician. Results of multivariable analysis showed that body mass index (odds ratio [OR] = 0.890, 95% confidence interval [CI] = 0.826-0.960), heart failure (OR = 0.325, 95% CI = 0.142-0.742), coronary artery disease (OR = 0.162, 95% CI = 0.069-0.379), smoking (OR = 3.852, 95% CI = 1.194-12.433), hypertension (OR = 10.584, 95% CI = 4.648-24.103), and dysrhythmia (OR = 9.339, 95% CI = 2.035-42.853) were associated with the use of dietary herbal supplements. Conclusions: Our results showed that dietary herbal supplements were commonly used by patients with chronic cardiovascular diseases. Therefore, understanding the interactions between the herbal supplements and drugs is necessary for minimizing adverse reactions.