Assessment of the quality of reference books on botanical dietary supplements

OBJECTIVE: To review books on botanical dietary supplements (BDS) targeted to pharmacists and physicians to assess their overall quality as primary and secondary reference books. DESIGN: We purchased 52 books for initial review based primarily on their titles. After eliminating books not written for health care professionals and books that contained very limited information on BDS, we selected 22 texts to review in depth. PARTICIPANTS: The review team consisted of four pharmacists--two with PhDs in pharmacognosy, one with a PhD in pharmaceutics, and one with a PharmD who is a senior medical student. RESULTS: The authors, reviewers, and editors of some books were highly qualified; others lacked the qualifications to summarize scientific information in a balanced, unbiased manner. Many books contain unsubstantiated statements. The books judged to be of the highest quality provide primary references to support all statements and advise the reader that insufficient information is available to assess potential drug interactions and safety during pregnancy and lactation. CONCLUSION: The quality of the information presented in the reviewed books varies dramatically. The most critical information gaps include the potential for drug interactions and the safe use of specific botanicals during pregnancy and lactation.