“Some ayurveda practitioners have told me that doctors prescribing allopathy medicines often advise patients not to opt for ayurveda. Such doctors are anti-nationals.”

"God bless atheism" (3 August 2007) http://youtube.com/watch?v=y4mWiqkGy-Y
2007

The Other World (1657)
Context: The most competent physician of our world advises the patient to listen to an ignorant doctor who the patient thinks is very competent rather than to a competent doctor who the patient thinks is ignorant. He reason is that our imagination works for our good health, and as long as it is supplemented by remedies, it is capable of healing us. But the most powerful remedies are too weak when the imagination does not apply them.

Y así, enfermos, ojo alerta
y ningún médico admitan;
mueran de gorra sin dar
un real a la medicina.
Diente del Parnaso ('Parnassus' Tooth') (1689), 'Prólogo al que leyere este tratado’.
Quoted in Chambers Dictionary of Quotations (1997), p. 1038.

This has been reprinted many times with slight variations on the wording; it is part of a much larger quote directly from Edison published in 1903:
:Nineteen hundred and three will bring great advances in surgery, in the study of bacteria, in the knowledge of the cause and prevention of disease. Medicine is played out. Every new discovery of bacteria shows us all the more convincingly that we have been wrong and that the million tons of stuff we have taken was all useless.
The doctor of the future will give no medicine, but will instruct his patient in the care of the human frame, in diet and in the cause and prevention of disease.
They may even discover the germ of old age. I don't predict it, but it might be by the sacrifice of animal life human life could be prolonged.
Surgery, diet, antiseptics — these three are the vital things of the future in preserving the health of humanity. There were never so many able, active minds at work on the problems of diseases as now, and all their discoveries are tending to the simple truth — that you can't improve on nature.
:* As quoted in "Wizard Edison" in The Newark Advocate (2 January 1903), p. 1 according to research by Barbara and David P. Mikkelson at snopes.com http://www.snopes.com/quotes/edison.asp.
1900s

Slow Medicine: The Way to Healing (2017)

http://www.youtube.com/watch?v=4XWTHoMBJvk

Les médecins administrent des médicaments dont ils savent très peu, à des malades dont ils savent moins, pour guérir des maladies dont ils ne savent rien.
This attribution to Voltaire appears in Strauss' Familiar Medical Quotations (1968), p. 394, and in publications as early as 1956 http://books.google.pt/books?id=lCtCAQAAIAAJ&q=%22Doctors+are+men+who+prescribe+medicine+of%22&dq=%22Doctors+are+men+who+prescribe+medicine+of%22&hl=pt-PT&sa=X&ei=mbnWUsvDIfTB7Aaw_YD4Dw&redir_esc=y; the quotation in French does not, however, appear to be original, and is probably a relatively modern invention, only quoted in recent (21st century) published works, which attribute it to "Voltaire" without citing any source.
Attributed

This attribution to Voltaire appears in Strauss' Familiar Medical Quotations (1968), p. 394, and in publications as early as 1956 http://books.google.pt/books?id=lCtCAQAAIAAJ&q=%22Doctors+are+men+who+prescribe+medicine+of%22&dq=%22Doctors+are+men+who+prescribe+medicine+of%22&hl=pt-PT&sa=X&ei=mbnWUsvDIfTB7Aaw_YD4Dw&redir_esc=y; the quotation in French does not, however, appear to be original, and is probably a relatively modern invention, only quoted in recent (21st century) published works, which attribute it to "Voltaire" without citing any source.
Original: (fr) Les médecins administrent des médicaments dont ils savent très peu, à des malades dont ils savent moins, pour guérir des maladies dont ils ne savent rien.