How much medicinal marijuana do you have to take to get you high?

Depends: You're not supposed to get high on medicinal mj! you're supposed to get pain or nausea relief. Medicinal marijuana has its thc content limited by statute. Domestic mj has on average 40% thc. Most statutes limit thc to less than 20%. How high you get is very individual & dependent on many factors. But your question implies your are trying to "game" the system by illegally using medical mj.