I took this at the onset of a horrible cold at the beginning of this year, and it instantly made me feel sick. It gave me a stomachache so bad I couldn't stand up, because having my insides stretched out hurt. It gave me a splitting headache, and sent me to the bathroom multiple times. I would rather have had a cold. I had gotten a sample through another testing site, and in a review I left, somehow the company that distributes Mucinex got ahold of my information and contacted me. They sent me a long winded form email asking me too many personal questions. I complained further, including a complaint about the unsolicited contact and inappropriateness of asking such personal questions, and a few weeks later- received the same form letter again. That's unacceptable, I asked to NOT be contacted any further regarding the issue. I don't know, maybe they thought I'd sue or something. Stupid. Anyway, in the time between the first email and the second, I had tried it again with the same results, I thought perhaps it had been a fluke the first time, but when it happened a second time- this product went right in the trash. It was extremely strong, too, burned my throat like liquor all the way down. At least liquor tastes better.