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1. The Effects of Garlic on
Platelet Aggregation: A
Systematic Review
Nguyen, S.; Stalcup, S.; Kaur, P.; Nair, A.; Nirankari, R.; Norbert, J.; Kaur, J.

2. The Effects of Garlic on Platelet Aggregation: A Systematic Review
Nguyen, S.; Stalcup, S.; Kaur, P.; Nair, A.; Nirankari, R.; Norbert, J.; Kaur, J. ; Singh, B.
Garlic is widely used medicinally throughout
history, and still today. Various studies have
been conducted to determine the full effects
of garlic in the human body.This review
analyzes multiple articles in attempt to
decipher the significances of garlic against
platelet aggregation and fibrinolytic activity.
Fourteen articles were originally gathered and
assessed for quality using an RCT scoring form
with a scale of 1-26. In six of the ten articles
reviewed, it was suggested that garlic may
express antiplatelet activity opposed to four
separate articles in which it was considered
insignificant.
In this study, 10 journal articles investigating
the effect of Garlic on platelet aggregation
and its fibrinolytic activity were evaluated. Of
the 10 articles, 6 showed Garlic inhibited
Platelet aggregation and plasma fibrinolytic
activity. Some of these results showed
increased bleeding time and decreased plasma
fibrinogen. The findings of the other 4 studies
demonstrated that Garlic had an insignificant
effect on platelet aggregation or fibrinogen
activity.
Overall, we felt that the studies were
inconclusive. We found that a majority of
articles did not do a power calculation and
that none of the authors compared the
dropouts of the studies to the ones who
completed the study. Additionally, one study
only went on for one week before drawing its
conclusions, which we did not feel was an
adequate study time frame based on the other
studies performed. Finally, not all studies
were double blind, which we feel could skew
their results. Finally, the articles had
conflicting results, which may be accounted
for by the way the study design, the type of
garlic administered and/or the study
population.
In conclusion, we want to acknowledge that
bias may have been made from our part due to
the lack of full access to wide variety of
resources, which could have affected the
outcome of this study. Further investigations
are needed to either strongly support or
oppose the garlic’s ability to inhibit platelet
aggregation, as the majority of the papers we
read concluded no significant correlation
between garlic and platelet aggregation.
Coagulation also known as clotting is the
process in which blood changes from being
soluble (liquid) to insoluble (gel). This
happens by a series of reactions that occur
when there is any type of damage to a
blood vessel. This process includes the
activation, adhesion, and aggregation of
platelets. The aim of our research is to
investigate the effect of garlic on platelet
activity and fibrinogen. In most of the
articles that were researched, platelet
aggregation / platelet
activation were the
outcomes
that were measured in
regards to garlic. Garlic is
known to lower cholesterol
and blood pressure as well as prevent
several other cardiovascular diseases. Along
with medical benefits of garlic, it is known
to reduce platelet aggregation. So, garlic
use in patients on anticoagulation therapy
is discouraged because it increases the risk
of bleeding in these patients. The aim of
our project is to review different clinical
studies done on healthy individuals and
patients with cardiovascular diseases to
determine the effects of garlic and its
different forms of extract on platelet
activity.
A total of 14 articles were gathered using
PubMed, Ebsco, PubMed Central, JSTOR, and
Highwire over a period of time. The search
criteria included garlic, whether in liquid or
powder pill form, correlative terms related to
platelet aggregation, such as fibrinolysis and
thrombosis, and Randomized Control Trials
(RCTs). The articles were then scored using a
Singh RCT score form. Scores ranging from 18-
26 were considered of high-quality and those
that did not meet this standard were
excluded. Quality articles presented with good
study design, proper randomization and
blinding, and a proper description of all the
variables used in the study. (Table 1) of the
12 articles gathered, 10 articles met the
appropriate protocols while 2 were excluded,
having scores of 15.
Medical University of the Americas
ABSTRACT INTRODUCTION
MATERIALS & METHODS
RESULTS DISCUSSION
CONCLUSION
ACKNOWLEDGMENTS

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