Netflix says it's going to cut back on how often smoking is shown in its original shows.
It's after a report said programmes on the streaming site showed "much more tobacco" than on US TV or cable.
Netflix says smoking in programmes aimed at younger people will only be allowed for "reasons of historical or factual accuracy".
In other shows it will only be shown if "it's essential to the creative vision of the artist or character-defining".
Netflix says it "strongly supports artistic expression".
It added: "We also recognise that smoking is harmful and when portrayed positively on screen can adversely influence young people."
The new rules came as report was released into cigarette use on screen by the US group Truth Initiative - which campaigns for people to lead "tobacco-free lives".
It compared the number of times tobacco products were seen in different series of Netflix shows that are popular with 15-to-24-year-olds.
They included Orange is the New Black, Stranger Things and House of Cards.
The report found - in all the Netflix shows it studied - cigarettes were more common in the later series than the earlier series.
The report also found, on the whole, smoking is being shown more on Netflix than on popular shows on US cable TV - like The Big Bang Theory and The Walking Dead.
Even in those shows, though, the rate is still rising.
Truth Initiative does say it only focused on Netflix because it's so popular - and shows on other streaming services, like Amazon Prime, show similar trends.
"Smoking on the small screen has gone from common to nearly unavoidable," the report says.
"While smoking in TV programmes has not been studied as extensively as tobacco imagery in movies, it is reasonable to conclude a similar harmful impact is possible."
In the UK, shows broadcast on TV have to follow rules put in place by a organisation called Ofcom.
They say that smoking in shows likely to be seen by under-18s "must generally be avoided and in any case must not be condoned, encouraged or glamorised".
And even in shows designed for adults it can be controversial.
More than 70 people complained about seeing smoking on Love Island in 2017 and the issue even got raised in the House of Lords.
The show has since got rid of its on-screen smoking area.