Saturday, July 11, 1998 Published at 23:46 GMT 00:46 UK
Abiola died 'a natural death'
Chief Abiola's eldest son Kola at his father's burial
The jailed opposition leader's death came one day before his expected release and led many, particularly in his family, to allege that he was poisoned by the military government.
The doctors said they believed poisoning was an extremely unlikely cause of his death, but that laboratory tests still needed to be carried out.
Tissue samples are to be sent to London and it may be another month before results are known.
The experts said some people had expressed concern to them about the treatment Chief Abiola received during his four years in prison. The doctors believe these concerns deserve further consideration.
At a press conference in Lagos, where the post mortem findings were announced, one of Chief Abiola's wives said she still held the government responsible for her husband's death.
The findings - by a team drawn from the US, the UK and Canada - were announced a short time after the burial of Chief Abiola in the garden of his home, mourned by hundreds of supporters and family members.
A correspondent described the funeral as noisy, but short, with the burial service lasting only 10 minutes.
Amid loud wailing from mourners, there were chaotic scenes as people tried to get a last glimpse of his body, which was lowered into the grave in a simple white shroud.
But many other mourners were kept away from the area by a security cordon.
Family members remained locked inside the house for most of the day as they mourned in private.
Chief Abiola's son Kola had appealed to the crowds not to allow violence during the funeral.
The body had been released to the family a few hours earlier after the completion of the post mortem examination.
He collapsed while meeting a US delegation in Nigeria to discuss the transition to civilian rule and died a short time later in hospital.
Riots in south-west
Earlier on Saturday, several people were injured in riots in the south-western town of Ibadan, which has a large community from the north of Nigeria.
People in the south-west, where Chief Abiola came from, are furious that he died while still in detention ordered by military rulers who come from the north.
The latest trouble follows two days of rioting in Lagos and Abeokuta, his home town. Up to 60 people are reported to have died during the violence.
Chief Abiola was widely believed to have won a presidential election campaign in 1993, which was annulled by the military. He was jailed the following year when he declared himself president.