Yes, although it depends on the medication you are taking. For example, CBD may delay the break-down of blood-thinning medication, causing it to linger in the body for longer than is recommended. This can cause the drug to not work properly and may complicate your medical condition. However, CBD has also been found to improve the way certain drugs act, perhaps allowing the dosage of the prescription drug to be lowered. Not all drug interactions are bad, but you should consult with your health practitioner beforehand.