I don't have kids, but when I searched for both "How to stop a cough" and "How to stop a child's cough",  there were MANY more results that came up for the search "How to stop a child's cough", so I decided to go with that title.  (Call me a sheep, I don't care.)

When I was a kid, Mom used to put Vicks VapoRub on my chest when I would catch a cold, and then make me put a shirt on to go to sleep.  The VapoRub did two things:  it kept my chest 'feeling' warm, and the mint smell helped keep my sinuses open.  She never put it on my feet, though, when I had a cough.

As with many things I read on the internet, I passed this one by Snopes.com, and the status was listed as UNDETERMINED.  I don't know why putting it on your feet keeps you from coughing, but many people are experiencing success with this home remedy!

CJ recently posted a story about how sodas are killing us, which I found to be interesting (in January, I decided to give up sodas.  I have lost 15 pounds so far!!).  I would notice that when I was sick, drinking sodas would make my cough worse.  It could be my imagination, or it could just be how I reacted to sodas, but when I saw his story I thought it reminded me of my cough getting worse when I did drink them...

(Okay, here comes the disclaimer:  this story is not to be used to treat, diagnose or otherwise explain away your symptoms/illness.  If conditions persist, see a doctor.  Don't let a life balance on rumor; seek professional help!)

By the way, I am going to start including a "TL;DR" line on my stories (which stands for Too Long; Didn't Read) to allow you to get the "Cliff's Notes" so-to-speak.  Here goes:

TL; DR:   When your child goes to bed, rub a little Vicks VapoRub on their feet, and then make them wear socks to sleep.  That seems to keep them from coughing.

(Via Snopes and Momaroo)