Blinding and Randomization
Celery and placebo capsules were prepared similarly. They had identical shapes, colors, sizes, textures, and odors. The capsules were packed in the same containers with random code numbers. Hence, the participants, researcher, physician, and data analyzer were all blinded to the treatment and placebo groups essence. The coding of capsule containers and randomization were performed using 6-digit numbers obtained from the “random number table”. The first column of the random number table was assigned to the celery-washout-placebo group and the second one to the placebo-washout-celery group. The codes were written on a piece of paper and put into an opaque envelope. The envelopes were sealed and placed sequentially in a box and kept by the researcher and physician. The envelopes and their codes were assigned sequentially to eligible participants in order of their arrival time.