Herbs are typically thought of as being considerably gentler and slower alternatives to drugs but it is also a fact that there are a great many potent, fast acting substances in nature and that people, for thousands of years, wherever they went in the world, have been diligent at finding those substances and learning how to use them.
There is a roughly accurate proportional law of medicine that the stronger and faster acting a substance is, the more likely it will be dangerous and cause side-effects.
There are very few herbs used in a modern herbal practice today that run the risk of serious side-effects. The quickest acting and somewhat dangerous plants, those from which many drugs such as morphine, digitalis, atropine etc. come from have generally long been adapted into pharmaceuticals.
We do however, still retain many plants in common use that work fast. Here is a short list of some of my own favourite, quick acting herbs. Read more about any that interest you by clicking on their links: