when my son catches cold cough, this is my favorite home-remedy...and it never fails me!!
a tbsp honey+ pinch of blackpepper 3-4 times in a day. lots of lukewarm water to drink throughout the day...i have seen this working like magic for cough..blackpepper takes the sting out, while honey soothes the throat.
i also use peppermint oil+ lavender oil+ teatree oil(all in equal proportions) on chest, throat and nose.it relieves the congestion.