Mandela's Indian-origin physician Vejay Ramlakan revealed several undignified episodes at the end of Mandela's life as well as bitter family squabbles over his care and legacy.
"I condemn the book in the strongest terms," Graca Machel said in a statement released by her charity foundation, local media reported.
"I am taking legal advice on whether to institute legal proceedings against the author and its publisher."
Machel accused Ramlakan of breaching patient confidentiality with his candid book, which was released to coincide with Mandela Day on July 18, an annual day to honour his memory.
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In the book, titled "Mandela's Last Years", Ramlakan reveals that an ambulance transporting Mandela to hospital during his final months caught fire on the highway forcing him to wait 30 minutes to wait for a backup.
He also detailed how the liberation hero regurgitated blood due to a lung infection and disclosed that after Mandela's death at the age of 95, a spy camera was found in the morgue where his body was held.