there actually are ways to "regulate" streghts of plants. THe ground it grows in. Season and time of day and month it is picked. May not be as strict as in pharma... but it's not like there's SUCH A HUGE difference in strenght. This is not an X or acid from backalley.

And as "you just can't" there's many yous out there who did it. For some people herbs are sufficient. I am not mixing. Many herbs though are well safe to mix with prescription meds.