Mucinex DM...

I meant to post the grapefruit one in FAQ as well. Anyway, I was just reading that if I use the DM Mucinex this is not what I want. Apparently I got the wrong mucinex, I should have only gotten the one containing Guifanesen, this contains that but it also contains dextromethorphan as well (cough suppressant. Hmm a waste if 10 bucks? Also, noted that on that site they said they bought a generic mucinex for like 4 bucks. I shop at Walmart (don't like Kroger) I didn't notice a generic. Anyway, feedback on the DM would be great if you know. It could be working against me. Hope not.