Well.....the best I advice I have for anyone of any age is to eat well (a good balanced diet) and get lots of sleep. The herbs can do little for you if you are not eating and sleeping well. These are better medicine than any herb, in my opinion, for fighting colds.

Getting enough sleep into a 2-year old shouldn't be difficult but if a balanced diet is an issue, an age-appropriate multi-vitamin might help to round out anything that is missing from their diet. Food is the best way to get your vitamins but sometimes kids just don't get all they need.

Keeping their hands clean, especially before eating, coming home from the store, etc., can help avoid colds in the first place.

FataMorgana

by 'cold' I take it you mean the sniffles, maybe a cough, without a fever?

lots of fluids, especially fruit juices (go for low-sugar ones) and hot teas - red zinger is a good choice, most kids will give it a try just for the color.

plain old saline nose sprays are best for kids - they help rinse the snot out, and sooth stressed out membranes at the same time.

eucalyptus oil, either on a cotton ball/ sachet/ washcloth or a few drops in a pot of steaming water will also help congestion.