The letter was published by Dr Duncon's employer in 1606
Doctors in the 17th Century were worried about the dangers of young people smoking, a recently unearthed letter has revealed.
The letter, written in 1606 by Dr Eleazar Duncon, said tobacco was "hurtful" to the nation's youth.
It was found by library staff at the Royal College of Physicians of Edinburgh (RCPE).
The Scottish Parliament will this week debate new proposals to curb tobacco and cigarette sales to youngsters.
Dr Duncon's letter reveals medical professionals were similarly concerned about the issue four centuries ago.
The letter, which was published at the time by Dr Duncon's employer, concluded that tobacco "is so hurtful and dangerous to youth that it might have the pernicious nature expressed in the name, and that it were as well known by the name of Youths-bane as by the name of tobacco".
Professor Sir Neil Douglas, the president of the RCPE, said it gave a "fascinating insight into historical concerns" about smoking and young people.
He added: "This letter from our library collection provides a fascinating insight into historical medical concerns about the addictive nature of smoking and young people, and shows that this issue has been of concern for over four centuries.
"The Scottish Parliament has already taken a political lead, and demonstrated its commitment to tackling the harm caused by tobacco, by introducing smoke-free legislation for public places.
"However, it would be easy for politicians to think that the problems associated with tobacco have been dealt with and to lose sight of the fact that the proposed bill includes critically important measures aimed at reducing smoking in young people."
The professor urged MSPs of all parties to take the "historic opportunity" to back the proposed bill, which would end point of sale advertising and tobacco vending machines, which he said encouraged and influenced young people to smoke.
If it is passed by Holyrood, the Tobacco and Primary Medical Services (Scotland) Bill would also introduce a registration system for tobacco retailers.
MSPs on the health and sport committee have also urged the government to include a provision in the proposed legislation that would make it a criminal act for adults to buy tobacco for under-age youngsters.