The nursing librarian makes a point to purchase evidence-based books on herbs and supplements for this class, so the Library has a fairly large collection. Most of them are in print, so you will have to make a trip to the building, but it's worth it!
Try searching your herb or supplement in GILFind, but also take a look at these books. Please remember that everyone in your class will want to use these, so consider putting them back on the shelves when you are finished using them.
Natural Standard Herb and Supplement Guide by 
Herbal - Drug Interactions and Adverse Effects by You can also find evidence-based information on the web, but you have to be more careful. Sites like LiveStrong or Wikipedia may have accurate information, but it may not be evidence-based, so don't use it.
Consider using one or more of these sites for your information.
About Herbs
This Web site for consumers and healthcare professionals provides objective information and a clinical summary for each agent and details about constituents, adverse effects, interactions, and potential benefits or problems. It's hosted by the Memorial Sloan Kettering Cancer Center. Evaluations of alternative or unproved cancer therapies also are given.
Complementary and Alternative Medicine Index
This is a University of Maryland index.
HerbMed
HerbMed is a searchable database which provides hyperlinked access to the scientific data underlying the use of herbs for health. It is an evidence-based information resource for professionals, researchers and the general public.
Mayo Clinic Drugs and Supplements Guide
The Mayo Clinic provides brief, evidence-based overviews of herbs and supplements.
Medicinal Herb Garden – Images
Located on the campus the University of Washington in Seattle, the Medicinal Herb Garden is a resource for herbalists, medics, and botanists of all levels. The site contains high quality photographs of a wide variety of herbs.
National Center for Complementary and Alternative Medicine
One of the Institutes at the National Institutes of Health (NIH), NCCAM is dedicated to exploring complementary and alternative healing practices in the context of rigorous science, training researchers, and disseminating authoritative information to the public and professionals. The site contains general information on complementary and alternative medicine, research and clinical trials.
NOAH-Complementary and Alternative Medicine
NOAH (New York Online Access to Health) provides access to high quality consumer health information. NOAH volunteers (librarians and health professionals) find, select, and organize full-text consumer health information that is current, relevant, accurate and unbiased.
Still need more?
Try this list of reputable health sites from WellCommons, or this list from the Medical Library Association CAPHIS group.
The library also pre-pays for high-quality online content that is not freely available on the web. You can access these resources from on or off campus. If you're off-campus, use your Campus ID to access these as with our other electronic resources.
Alt HealthWatch
Alt HealthWatch is an EBSCO database that allows you to search by herb name. You can also type in other search terms, like applications, active ingredients, usage, side effects, adverse reactions, or drug interactions. Here's a sample search for echinacea AND side effects.
Medline Plus
Medline Plus is an appropriate database as it provides a Drugs & Supplements page. From there you will see an alphabetical list of Herbs and Supplements. Check to see if your herb is listed. If it is, you will find useful information about your herb, even a report card grading its usages/applications. Each entry includes a Selected References section that will provide you with scholarly articles related to your herb.
