The cardinal leading the Vatican's charge against The Da Vinci Codeurged Catholics today to shun the novel like rotten food and branded the bestseller "a sack full of lies" insulting the Christian faith.
In an interview with Reuters, Cardinal Tarcisio Bertone also said Catholic bookstores should take the novel off their shelves and accused US author Dan Brown of "deplorable" behaviour.
The novel is an international murder mystery centred on attempts to uncover a secret about the life of Christ that a clandestine society has tried to protect for centuries.
"A lot of novels do good but this book is rotten food ... it does harm, not good," Cardinal Bertone said in the 30-minute interview in the offices of the Vatican's doctrinal department.
"This book is a sack full of lies against the Church, against the real history of Christianity and against Christ himself," added the archbishop of northern Genoa.
The central tenet of the book is that Jesus married Mary Magdalene and had children.
"We can't keep quiet about the truth when faced with all the lies and all the inventions in this book.
"Some of the gross falsehoods include the treatment of the death and the resurrection of Christ, which is the central mystery of Christianity," he said.
His comments are significant because he is close to Pope John Paul and until 2003 was deputy head of the Congregation for the Doctrine of the Faith, the Vatican's most powerful office.
Speaking as one of the Church's top theologians, he said the book sows doubts and dangerous confusion among the faithful.