Staff at the clinic near Basel told Sky News that Dr Goodall had “gone in peace”.
Sky’s Michelle Clifford said she could hear Beethoven’s 9th Symphony coming from the room where he was being helped to die.
David #Goodall with his family who are filling out witness forms ahead of his assisted suicide says “what are we waiting for?”. He tells me he is certain he has made the right decision as his life has been very hard in recent years pic.twitter.com/iteul01vuU
— Michelle Clifford (@skynewsmichelle) May 10, 2018
The world-renowned ecologist had told reporters he might play Ode to Joy from the symphony to accompany his death.
He died at the moment the song concluded, said Exit International – a campaign group that helped Dr Goodall travel to Switzerland.
As his family filled out witness forms ahead of the procedure, Dr Goodall asked: “What are we waiting for?”
He asked for no funeral or remembrance ceremony.
Yesterday, while wearing a jumper with the words “Aging Disgracefully”, he told a packed news conference: “There are many things I would like to do, but it’s too late.”
“I’m content to leave them undone,” he added.
Four family members and a close friend had travelled to be at his side when he ended his life.
Dr Goodall, who was not terminally ill, told reporters on Wednesday: “One should be free to choose the death, when death is at an appropriate time.
“My abilities have been in decline over the past year or two, my eyesight over the past six years.
“I no longer want to continue life.”
The 104-year-old chose to take the lethal drug Nembutal intravenously.
Dr Goodall turned the wheel himself to start the solution flowing and had the option to change his mind at any time.
Assisted suicide has been legal in Switzerland since the 1940s if performed by someone with no direct interest in the death.
Dr Goodall was born in London in 1914 and moved in 1948 to Australia, where he was a lecturer at the University of Melbourne.
He produced dozens of research papers and until recently continued to review and edit for different ecology journals.
David has requested that his body be donated to medicine and, if not, that his ashes be sprinkled locally,” said Dr Philip Nitschke from Exit International.
“He wishes to have no funeral, no remembrance service or ceremony. David has no belief in the afterlife.”
Last month, he told Australian broadcaster ABC: “I greatly regret having reached that age (104)…
“I’m not happy. I want to die. It’s not sad particularly. What is sad is if one is prevented.
“My feeling is that an old person like myself should have full citizenship rights including the right of assisted suicide,” he added.
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Assisted suicide is illegal in most countries around the world and was banned in Australia until the state of Victoria became the first to legalise the practice last year.
But that legislation, which takes effect from June 2019, only applies to terminally ill patients of sound mind and a life expectancy of less than six months.