The asymmetric unit of the title compound, (C(15)H(25)N(2)O(2))[FeCl(4)], contains a tetra-chloridoferrate(III) anion and a oxymatrinium cation [oxymatrine is (4R,7aS,13aR,13bR,13cS)-dodeca-hydro-1H,5H,10H-dipyrido[2,1-f:3',2',1'-ij][1,6]naphthyridin-10-one 4-oxide]. The conformation of oxymatrine is similar to that of matrine with one ring having a half-chair conformation, while the others have chair conformations. Chiral chains of cations along the c axis are formed by O-H⋯O hydrogen bonds.