The title compound, C(11)H(8)O(3), was isolated from Impatiens balsamina plants (balsam, LIB) grown in our laboratory. The two six-membered rings of the naphthalene-1,4-dione unit are coplanar [maximum deviation = 0.009 (1) Å]. The O and C atoms of the meth-oxy substituent also lie close to the naphthalene plane, with deviations of 0.0090 (2) and 0.047 (2) Å, respectively.