I doubt if "die off" has anything to do with it. Some herbs, as well as pharmaceuticals, drugs, or even certain foods, can effect users with various symptoms. The compound simply doesn't "agree" with you, or perhaps quantity is the issue. These herbs are used because they have what are, in essence, toxic qualities about them which can (sometimes) effectively kill off certain organisms. That some folks might feel some sort of discomfort after taking same doesn't surprise me. If the discomfort continues, you might try altering the dosage or trying another formula.