What Are Side Effects Of Drinking Excessive Bekunis Tea?

I am concerned about my mother who had constipation since a young age. She's 45 this year and still has the same problem. To resolve it, she drinks a kind of tea called Bekunis, which is not meant to be harmful in the short run in controlled dosages, but my mother takes four times the recommended dosage, once to twice a week. This has been her routine for years now. I am worried that continuously inducing what eventually turns out as diarrhea will take a toll on her health in the long run. Would like to confirm the extent of impact of this on her health and what would be an appropriate course of action to take. She is not keen on going to the doctor and dislikes the usual medicine prescribed because it is too 'sweet.' I suspect that she is suffering from bullemia, as she also does not eat full meals at times and repeatedly offers the rest of us food when we tell her we are full. She currently weighs 45.5kg and is 1.6m tall. Your help is greatly appreciated.