I always keep a jar of raw honey in my pantry not only for the occasional cold remedy: a nice cup of lemon + ginger tea with some honey but also for baking or to sweeten food or drinks.
Regular honey is pasteurized vs raw that has not been heated or filtered.
Manuka honey is, simply put, raw honey that comes from the Manuka plant that grows in New Zealand.
It is rated by UMF (Unique Manuka Factor): the greater the number, the higher its antibacterial activity. When buying it, make sure you read the label carefully.
I use it to relieve sore throat, to calm mouth ulcers and to support my gut. Because it contains pre-biotics, Manuka honey helps feed good bacteria in the gut.
It is advisable to consume with moderation: even if its GI (Glycemic index) is lower than regular sugar it is still high in carbohydrates so a little tsp goes a long way!