I don't really use cough medicines. With my son's asthma-like allergies, it's actually a bad thing to try to "suppress" his cough, so we never really use them with him. I have to use antihistamines with him. With our daughters, who don't have his allergies/breathing challenges, the one or two times I tried a cough suppressant, it didn't really help them. Especially if it was a cough due to post-nasal drip from a cold, or a really congested/bronchial cough. A hot steam bath, or a walk out in the night air tends to help that. I also use saline solution to help thin out the nasal congestion, which is the main culprit for the cough in most cases. The only cough suppressant that I've ever used that actually did something was one called Delsym. If they have like a dry, remnant cough, that was kind of the tail-end of a cold that would bother them at night, I'll use that and it works well. Thankfully, my kids are pretty healthy so I haven't needed to worry about using these too often. All that to say, no, I don't think they really work a whole lot. I'm more of a try natural remedies first, before pumping them up with med's. I'll use med's if I need to, but it's not the first thing we turn to. Extra vitamins, and natural remedies to help soothe a cold/cough. I had given up on a lot of these over-the-counter "remedies" a long time ago...

i find that most times a cough is caused by post nasal drip so often, an antihistamine will work better than actual cough medicine. if the cough is "tight," rather than a suppressant, give them an expectorant to losen it up. they'll have a couple of days of discomfort but in the end, they'll be able to "expectorate" all that garbage out. And...LOTS of fluids.