Abstract. We use recent calculations of the Zeeman splitting of neutral helium lines and atmospheric models to investigate the properties of the magnetic DB white dwarfs in the field range 10-1000 MG. We confirm that GD 229 exhibits spectroscopic signatures indicative of neutral helium in a magnetic field of ∼500 MG, and argue that HE 1043-0502 may also be helium rich with an even higher field of ∼750 MG. The dominant features in the phase-averaged spectrum of the polarized magnetic white dwarf HE 1211-1707 correspond with those of Zeeman split neutral helium lines in a mean field of ∼50 MG, while the observed spectral variations point to a non-dipolar field structure.