Intended for healthcare professionals


Evidence based medicine: what it is and what it isn't

BMJ 1996; 312 doi: (Published 13 January 1996) Cite this as: BMJ 1996;312:71

Evidence Based Medicine as Frame of Phytotherapy

Editor - Evidence-based medicine has emerged as a powerful problem-
oriented approach to the practice of medicine that seeks to improve
patient care by considering the quality of clinical evidence. Evidence
based medicine is founded upon an ideal that decisions about the care of
individual patients should involve the "conscientious, explicit and
judicious use of current best evidence." (1)

From an ethical perspective, the strongest arguments in support of
evidence based medicine are that it allows the best evaluated methods of
health care, useless or harmful methods to be identified and enables
patients and doctors to make best decisions. Medical decision making draws
upon a broad spectrum of knowledge including scientific evidence,
individual scientific medical education, personal experience, personal
biases and values, economic and political considerations, and
philosophical and social principles ; it may be not always clear how
practitioners integrate these factors into a final decision, but it seems
unlikely that medicine can ever be free of personal and intuitive
judgments. For this reasons evidence based medicine recently has undergone
to a cross fire of criticisms, where it is sometimes depicted as a method
to improve more statystical analysis of pathologic cases, than clinical
decision making to get the best treatment for a single patient.

While clinicians are exhorted to use up to date research evidence to give
patients the best possible care, actually doing so in individual patients
is difficult: at the heart of clinical medicine it is an unresolved
conflict between the essentially case based nature of clinical practice
and the mainly population based nature of the research evidence, and this
is particularly truthful for phytotherapy. In phytotherapy besides usual
problematics of medical research are added the specific issues of the
vegetal extract: its qualitative and quantitative variability, different
types of extraction, phenotipic and genotipic variabilities of vegetal
drugs, different methods of growth, time of harvesting and preservation,
gographical and climatic differences (2).

We believe that in the field of phytotherapy research, evidence based
medicine is not only an unvaluable tool , but the sine qua non to verify
efficacy , tollerability and safety of a herb extract.
Metanalysis on Hypericum perforatum (St. John's Wort) (3) , a drug used
for depression by millions of patients in all over the world, and for a
long time considered just a placebo, recently thanks to important
metanalysis it is now considered a valuable tool for the treatment of mild
and medium depression. In the same way metanalysis on Allium sativum
(Garlic) 4); Serenoa Repens (Saw palmetto) (5) and Menthae piperitae oleum
(Peppermint oil) (6) confirmed the pharmacological activities of these
herbal extracts.

Besides, evidence based phytotherapy is an unique tool to evaluate herbal
drugs in a field where tradition and popular empirism is still very
strong. The development of research on the basis of evidence medicine is
an important international priority in response to the public's growing
use of complementary therapeutic interventions and recent emergence of
drug interactions; and it has to be conducted following parameters
characteristic and proper of phytotherapy.


1. Sackett DL, Rosenberg WMC, Gray JAM, et al.: Evidence based
medicine: what it is and what it isn't. BMJ 1996; 312: 71-72.

2. Firenzuoli F, Gori L.: Evidence-based phytotherapy .Recenti Prog
Med, Nov 1999, 90(11) 628.

3. Stevinson C; Ernst E .:Hypericum for depression. An update of the
clinical evidence.
Eur Neuropsychopharmacol 1999 Dec;9(6):501-5 .

4. Neil HA; Silagy CA; Lancaster T ;et al.: Garlic powder in the
treatment of moderate hyperlipidaemia: a controlled trial and meta-
analysis.J R Coll Physicians Lond 1996 Jul-Aug;30(4):329-34.

5. Boyle P; Robertson C; Lowe F ,et al.:Meta-analysis of clinical
trials of Permixon in the treatment of symptomatic benign prostatic
hyperplasia. Urology 2000 Apr;55(4):533-5393.

6.Pittler MH; Ernst E .Peppermint oil for irritable bowel syndrome: a
critical review and meta-analysis. Am J Gastroenterol 1998 Jul;93(7):1131-

Firenzuoli F, Gori L.

Service of Phytotherapy - St. Joseph Hospital,
Via Paladini 15 - 50053 Empoli (Florence) - ITALY

Competing interests: No competing interests

15 August 2000
F Firenzuoli