She worked as a journalist for the newspaper Expressen from 1968 to 1978. Among her books are Skylla sig själv from 1976 (on rape), Heder och samvete from 1991 (on Swedish neutrality during World World War II), and Mediernas svarta bok from 2001. She made her fiction debut in 1979 with the novel Svensson, Svensson, a reply to Ulf Lundell"s novel Jack.
Boëthius was awarded Ture Nerman-priset in 1998 and Dan Andersson-priset in 2002.
In 2012 she took part in the Ship to Gaza mission with SV Estelle.