Yup. Supplements may have side-effects and may also react with prescribed meds. Those people who have more than one doctor treating them and prescribing meds should always inform those other docs about
what they're taking - and it might be a good idea to run it by the pharmacist. I would think this is a no-brainer but there have been so many incidents of patients taking meds prescribed by different doctors and experiencing terrible side-effects because of the different meds.
I would also suggest that people with serious health conditions have a bracelet that identifies their diseases and conditions.