If you are having problems with constipation, increasing fiber and water will do the trick. If you have a physical problem that results in long term constipation, your doctor should be your first contact.
The tea you referenced is a laxative. It doesn't help in digestion, has no healthy benefits, and has been known to have serious side effects. Besides overworking your bowels, there are ingredients in it known to have adverse effects on your heart and blood pressure.
There's a lot of marketing hype behind products like this. But they are not backed up by clinical evidence, and there are a lot of medical websites that warn against them.
Hope that helps