Former president Jacob Zuma's wife, Nompumelelo Ntuli-Zuma, is considering legal action against the police and the National Prosecuting Authority (NPA), her lawyer told News24 on Friday.
This follows a decision by the NPA not to prosecute anyone for Zuma's alleged poisoning.
In 2015, Ntuli-Zuma, was banned from his Nkandla compound by then state security minister David Mahlobo following "revelations" of her suspected involvement in a plot to poison Zuma, News24 reported.
"We are relieved that the charges have now been permanently withdrawn," Attorney Ulrich Roux, who is representing her said.
"She feels vindicated and is very annoyed. The NPA has insisted over the past five years that there is evidence linking her to this so-called poison plot and that she will be charged as a suspect.
"Now they confirm that there is no evidence of any plot and there is no evidence of anyone ever been linked to such a plot. She should never have been implicated on this bogus charge."
Roux said Ntuli-Zuma was weighing her options.
A letter to the Hawks written by acting KwaZulu-Natal director of public prosecutions, advocate Elaine Zungu, dated September 13, states that there is no evidence that Zuma was poisoned.
It also states that Zuma has not deposed to an affidavit detailing the alleged poisoning on his life and that she could not refer to him as a complainant.
"The SSA reports contain no evidence at all that Mr Zuma was poisoned, let alone by whom," reads the later.
MaNtuli is the second of Zuma's four wives.
The Sunday Times reported that in early August 2014, during a trip to the US, doctors diagnosed an ailing Zuma as having been poisoned.
However, not trusting US doctors, Zuma went to Russia later that month for treatment. Russian doctors reportedly confirmed the diagnosis.