I know that echinacea and Vitamin C are safe, although if you can get the Sodium Ascorbate version it is better (there is a great thread on the vaccine board about it). You might want to check out kellymom.com there is some good info there about what is safe to take when sick.
I started taking 2-3 glasses of these, along with my grippe formula of homeopathics from my dhm when my throat started hurting and so far I've had a VERY mild cold and my 5 week old seems to be ok too.
Enchincea is best at the very start of a cold/flu. Once it has a grasp on you it is best to take vitamin C rich herbs. Rose hips are good. Elderberries have C and are antiviral. Hyssop is amazing for colds and safe for babies. Use tea or tincture. Ginger and lemon tea is a favorite for colds. Usnea tincture may be hard to find, but I have found it indespensable when dealing with colds. It is a powerful yet safe antibiotic. Be well.
Please more info here! My "go-to's" are oil of oregano and thieves oil. Just googled it and oregano will cut my milk supply?!?! Can't find anything on thieves... Elderberry syrup is safe? What else can I do???