3.3. Quality of included studies
Based on Cochrane's risk of bias criteria, all of included studies
were rated high risk of bias. All RCTs were rated high risk of bias in
blinding domain because they used different dosage forms for
intervention and comparator. Two studies were rated high risk of
bias in sequence generation and allocation concealment domains
(Maneenual et al., 2010; Benchakanta et al., 2012) because they
used inappropriate method for randomization and allocation
concealment. None of included studies showed bias in incomplete
outcome data, selective outcome reporting and other sources of
bias. JADAD score of all included studies was also examined. The
methodological quality of included trials was low to medium with
JADAD score ranging from 1 to 3 of a total score of 5 (Table 3).