hello,
If you want to select all the column in the med table, just replace
* with
Med.* or you can use Med.column1, Med.column2, Med.column3, etc...
select med.* from Med,Active_material,Active_mat_med
where Med.Med_ID=Active_mat_med.Med_ID
and Active_material.Activemat_ID=Active_mat_med.Activemat_ID
and Active_material.Activemat_ID=@P_Activemat_ID