Are herbal medications and multi-vitamin/minerals useful?

This essay is divided into two topics.
First part consists of answering the questions: Are herbal medications and multi-vitamin/minerals useful? Are they a waste of your money? Are they harmful to your health? This topic should provide a lot of discussion among students. There are 3 parts to each of these 2 major topics; Herbal medicine (botanicals) and Multivitamin/minerals. Are they useful (give several examples of when and what for)? Could they be harmful to your health (give several examples of when and what possible symptoms)? So could they be a waste of money?
(Include 3 Academic Sources)

Second part is answering the following questions: What are hypersensitivity reactions (in general)?

For each of the 4 hypersensitivity types;

Give names for each type
What can cause (trigger or bring on) the reaction? List examples.
How are they manifested (symptoms)?
What are the mediators of each type of hypersensitivity reaction?
(3 academic sources to be used)