In a lower chamber judgement in May, the European Court of Human Rights held that Swiss law does not clearly specify in which cases assisted suicide is authorized, causing ambiguity, and a "considerable degree of anguish" for the applicant.
The woman, Alda Gross, is not suffering from any clinical illness but has wanted to end her life for a number of years because of old age and to avoid the "suffering (coming with) the decline of her physical and mental faculties".
Doctors refused to prescribe any potentially lethal drug doses and health authorities in her home region of Zurich also turned down her request.
Gross complains that by denying her the right to decide by what means and at what point her life would end the Swiss authorities breached Article 8 (right to respect for private and family life) of the European Convention on Human Rights.
Swiss courts had earlier ruled that Gross, who was born in 1931, did not fullfil the conditions set up by the Swiss academy of medicine as she did not suffer from any terminal disease.
In May, the ECHR did not rule whether assisted suicide should have been authorized in Gross's case.
But it ruled, by a majority, that there had been a violation of Article 8 of the European Convention.
It held in particular that Swiss law, while providing the possibility of obtaining a lethal dose of a drug on medical prescription, did not provide sufficient clarity of its guidelines on euthanasia.
No date has been set for the final ruling by the ECHR's Grand Chamber.
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