Homeopathy is garbage.
The general idea is that if you have a cold, you should take something that gives you cold symptoms, so that that substance will take over for making you sick. Then when you stop, you'll stop being sick.
Of course, they don't want to give you anything that will make you ACTUALLY sick, so they dilute it. Today, it's usually so dilute that to find one molecule of the stuff that's actually supposed to help you, you'd have to look through the equivalent to the whole galaxy in water molecules. The chance of even finding that molecule in a bottle of what you're buying is pretty thin.
It's water that works based on the placebo effect. If you get better, of course, it wasn't because colds naturally go away on their own, and the intake of water helps a bit. It's because of homeopathy.
Just deal with the cold, and don't waste your money.