There are a few types of scientific experiments done on herbs and synthetic drugs, it is good to know the difference;
A) Ex vivo/ in vitro studies: These are done on cell lines or alike. The results may not apply in humans and they may be at concentrations that are not relevant in herbal practice. They are not very reliable, but are important basic characterisation of herbs.
B) In vivo animal studies: These types of experiment are conduct on animals which researchers use to ‘model’ what the behavior of a herb would be in a human. Similar to ex vivo studies the results often do not replicate in humans, they also can be cruel and ethically dubious.
C) Open label studies: These studies are bias because the patient and investigator both know they are receiving treatment, which can give rise to the placebo effect.
D) Single blind clinical trials: These are studies where the patients do not know whether they are getting a herb or a placebo.
E) Double blind clinical trials: These are studies where both the patients and investigator do not know whether they are giving herb or placebo.
F) Placebo controlled: In order to compare against something patients are given a placebo treatment so that statistical analysis may be done of the group receiving real treatment versus that receiving false treatment.
G) Alternate medication controlled: The same as placebo controlled, but a different medication is used such as a synthetic drug.
H) Randomised: Patients are allocated treatment or control at random. Checks must be performed to ensure both groups have a similar gender and age balance.
Additionally be aware that studies may suffer from low power, meaning if they have a small number of patients they are not as reliable as those with a very large number of patients. Most studies on herbal medicine are low powered. The letter N refers to the number of people in a study.