A lot of herbal medicines are dose dependent. You can consume 1 clove of garlic and its a nice spice for food. but when you consume a dose of 4 or 5 garlic cloves it becomes antibacterial/antibiotic. Vitamin C in high dose (20+ Grams a day.) concentrated extracts of oregano,is a strong antibiotic,antiviral. Grapefruit seed extract. many things are just food seasonings at normal doses and become effective medicine in high dose concentrations.