This is the first time in my life that I took Mucinex. I am 62 years old! I had bad allergies for months from all the cottonwood floating around, my apartment! I had a bad cough, with a lot of mucus, and I was tired of it, and nothing helped with my allergies, I bough a few allergy meds, and even Benadryl! It was only a small temporary relief, for a few hours! So I bought some Mucinex, today from Amazon, and once it was delivered, I took one pill after 12:30 pm. An hour later I felt kinda dizzy, tired, sluggish, so I then laid down on my bed, to sleep it off, and my stomach started to hurt really bad, so I got up and took two tums for the stomachache, which helped a little, so I stayed up for a few more hours, until my stomach pain wasn’t as bad! Then around 7:00 pm, I was exhausted and still dizzy so I went to bed! Around 8:30 pm, I was suddenly woken up with the worst stomach cramps ever, and so much deep gut pain that I haven’t felt since I had the stomach flu many years ago. I went to the bathroom and I had the worst explosive water diarrhea it wouldn’t stop coming out, I was in the bathroom for at least 15 minutes, it felt like you’re peeing from your butthole, it was awful! The explosion diarrhea finally stopped at 9:00 pm, but I still have a dull and painful stomach ache, and I am up right now, and I can’t sleep!! The Mucinex did help with my deep cough, and the thick mucus, but my gosh the side affects are severe, I am never taking this medicine again!! I have read a lot of the reviews from others on this site, that unfortunately suffered the same after effects as I did tonight!! Please take Mucinex with caution, and expect bad side effects! Ughhh Oh great my tummy just rumbled loudly….I might be up all night!!! GrrrrRead More Read Less