I can recommend the book I use a lot.
The Herbal Drugstore.
ISBN 1-57954-532-7 Published by Rodale, written by Linda b white, and Steven Foster, reviewed by Dr Ian Banks.
It's the best one I have on using natural methods to treat ailments of all sorts. If you are interested in natural medicine, it's a must have on your bookcase.
I've recently had a nasty cold, all the symptoms were of the new floo that is going round but not so bad. Testing said I didn't have the floo, so I treated it from the book. Less than a week later, despite a bit of goo on the chest, I'm feeling spot on again.
Manuka honey and some extra b vits have sorted me out well, and mullion tea is fighting the goop nicely. It normaly goes on for weeks, and when something like this goes to my chest.. which it always does, I normaly need a course of antibiotics. This time I'm not needing any.
Mind you, I've spent a fortune on manuka honey, there is a shed load of garlic in my diet atm! Including 5 one a day mega stregth capsules. Luckily garlic overdose isn't a thing!
Cold sores are a nightmare. Treat with zorvirax at the first tingle, and often they can be prevented or at least minimalised. Often stress will bring them on, as that can also affect your immunity. So building up your immunity to colds etc can be a useful thing to do, especially if you are susceptible to cold sores.
I start a course of Echinacea every autumn to build up immunity, this autumn, I forgot, and ended up with a nasty cold, first one in many years.
I've started a medicinal garden, and get a lot of herbs that i need, but don't have, from Neil's yard. They are very helpful over the phone.