Randomization
All participants were randomly allocated to either propolis (n = 33) or placebo (n = 33) groups. Randomization was stratified according to sex (male vs. female), with the use of permuted block size of 4. The assignment sequences were provided by an independent statistician with the use of a random-number table and then were kept in opaque, sealed, numbered envelopes until the end of the eligibility criteria evaluation. Tablet containers were coded as A and B to order to allocation concealment. The study pharmacist coded tablet containers as A and B according to randomized list. Treatment assignments were concealed from researchers and all patients until the completion of data analyses, with the exception of the pharmacist.