Ugh, I typed a large post on here but it didn't go through. Neverthelesss, I will try again.
Firstly, honey is fantastic for colds! I recommend taking a spoonful in the morning and one before you go to bed.
Echinacea has in fact been used by America Indians for hundreds of years for colds. It increases levels of properdin, a chemical which activates the part of the immune system responsible for increasing defence mechanisms against virus and bacteria attacks.
Its anti-bacterial effect makes it a good herb for treating many viral and bacterial infections. Echinacea is also an excellent blood cleanser, it helps to sweep dead cells and other debris through the channels of the lymphatic system. And dispatches white blood cells to fight the infection.
No treatment of colds would be complete without Garlic. Garlic has anti-bacterial properties that help the immune system to fight infection, it is an excellent boost to the immune system. The reason for this is garlic contains several helpful compounds, including allicin, one of the plant kingdom's most potent antibiotics. Garlic combines well with echinacea and together make a strong fighting force against infections.
Onion is a close relative of Garlic and has similar properties, containing similar antiviral chemicals. Use onions and leeks in your cooking when you have a cold or are around people who do.
Ginger is another of natures' antiviral herbs. It contains nearly a dozen antiviral compounds. Ginger is pain relieving, antiseptic and antioxidant. It is valuable for preventing and treating colds, sore throats and inflammation of mucus membranes. Ginger reduces pain and fever and has a mild sedative effect that will encourage rest.
Also, you can make a tincture, include it in your food, whatever. A method my daughter likes if is if I include some garlic into a mild fruit smoothie.
Vitamin C is very good for the relief of cold symptoms and to help the body fight infection. The best source of vitamins is always fresh fruit and vegetables. Citrus fruit is especially high in vitamin C.
Sage is a traditional remedy of long standing for soothing sore throats as it has antiseptic and anti-bacterial properties. For an inflamed throat and hoarseness use a hot sage infusion or gargle with a sage, apple cider vinegar and honey mix. In feverish conditions, sage is very cooling. Take as a tea or tincture.
It reduces fevers by inducing sweating and cooling the body. It is also a painkiller for headaches and some migraines. It is a soothing decongestant and like eucalyptus, makes an effective inhalation for clearing blocked sinuses.
Lemons are a rich source of vitamin c, and taken hot in a hot lemon and honey drink, is a traditional remedy for colds and sore throats.
Steam inhalations of Juniper is beneficial for relieving congestion in coughs and colds. Add a few drops of the oil to hot boiled water, place your face over the bowl, cover with a towel, and inhale the steam. This is one I make my fiancee do when he has a cold. xD
From what I have experienced, tried and tested, these should all be effective. I hope the fact that i've included the science helps, too.