The white-rot fungus Bjerkandera adusta produces volatile chlorinated phenyl compounds. The main compounds identified were 3-chloro-4-methoxybenzaldehyde (3-chloro-p-anisaldehyde), 3-chloro-4-methoxybenzyl alcohol (3-chloro-p-anisyl alcohol), 3,5-dichloro-4-methoxybenzaldehyde (3,5-dichloro-panisaldehyde), and 3,5-dichloro, 4-methoxybenzyl alcohol (3,5-dichloro-p-anisyl alcohol). p-Anisaldehyde, veratraldehyde and the corresponding alcohols, p-anisyl alcohol and veratryl alcohol were produced simultaneously. Even with a very low concentration of chloride in the medium (< 10(-5) M), chlorinated aromatic compounds were still observed. Addition of bromide to the culture medium led to the production of brominated compounds : 3-bromo-4-methoxybenzaldehyde, 3-bromo-4-methoxybenzyl alcohol, 3,5-dibromo-4-methoxybenzaldehyde and 3-bromo-5-chloro-4-methoxybenzaldehyde. These brominated compounds have not previously been reported as natural products. Although iodo-aromatic compounds were not produced by supplementation of the medium with iodide, isovanillin was found in the culture broth under these conditions. This compound may be formed by substitution of the iodine intermediate by a hydroxyl group on the third carbon of the ring. Diiodomethane or chloroiodomethane were also found. It is the first time that the production of halomethane has been related to the production of halogenated aromatic compounds. All the strains tested have these capabilities.