- OBJECTIVE: To determine factors that predict disclosure of natural product use by patients to their primary care physicians. METHODS: An 18-item survey about health care use and communication was distributed to patients who presented to the Canadian College of Naturopathic Medicine in March 2003. We examined correlations between responses and created a multivariable logistic regression model to explore which factors were associated with patients' discussion of natural product use with their primary care physicians. RESULTS: The survey was given to 198 patients, 174 of whom responded (response rate, 87.9%). Most respondents (161 [92.5%] of 174) made use of natural products, and many (61 [41.5%] of 147) reported that they did not discuss natural product use with their primary care physician. The most significant factor predictive of patients having discussed natural product use with their primary care physician was having their primary care physician ask about natural product use (odds ratio, 18.77; 95% confidence interval, 5.06-69.62). Most respondents (107 [69.9%] of 153) indicated that their primary care physician did not ask about natural product use. CONCLUSIONS: An important number of patients who visit a naturopathic clinic do not disclose natural product use to their primary care physicians. Our findings suggest that disclosure rates could be improved by physicians taking a more active role in asking their patients about natural product use.