For myself, prevention for a condition like boils would be taking Echinacea when I feel I might be getting run down. Increased emotional stress, increased work load, poorer quality nutrition and less sleep and relaxation are signs of increased risk of infection and illness. This herb has helped many people to either prevent a problem or greatly lessen its severity. Common sense breaks are always a good idea from anything you take on a daily basis. After a break you can always change to a different herb as well.
Variety can sometimes boost effectiveness.
Lapacho is native to South America and has been used for medicine by native cultures for thousands of years. Its use has been much the same as the North American Echinacea except that its cancer treatment effectiveness is even more impressive. When used externally, many herbs have been recently researched and found to be effective for skin conditions including boils. Recent scientific findings, only confirming historical use, have recognized the high mucilage content of Mullein leaves and flowers as beneficial when applied externally to piles, itching complaints, burns, scalds and boils. Recent reports on Heartsease or Wild Pansy which contains saponins, describe its benefits for skin conditions when taken internally a tea and when used externally as a compress.