I am not familiar with sho-saiko-to.
After doing some research, I could not find a specific drug interaction between this herb and sulfasalazine - however that doesn't may that one does not exist.
Close monitoring of the liver enzymes can be considered to ensure that these combination of drugs does not do any hepatic damage.
I would discuss this question with your personal physician before starting on the regimen.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.
Kevin, M.D.
kevinmd_