Just because they're natural doesn't mean they're safe. Herbal supplements can have harmful effects when taken in improper doses or when mixed with other herbs or medications. Until recently, it's been a bit of a guessing game, but there is now a guide to navigating the confusing landscape of herbal dos and don'ts.

The Essential Guide to Herbal Safety [1] is 704 pages of comprehensive information on the safety of 125 herbs, covering everything from interactions and adverse reactions to toxicity and allergies.

Written by Simon Mills, Director of the Centre for Complementary Health Studies at the University of Exeter in England [2] and Kerry Bone, Head of Research and Development at MediHerb [3] and principal of the Australian College of Phytotherapy [4], The Essential Guide is probably the most up to date guide to herbal safety available today (it was published earlier this year).

The Guide has even received a glowing - if technical - review [5] from Francis Brinker, Clinical Assistant Professor of the Program for Integrative Medicine [6] at the University of Arizona.