user7622: The fifth precept started off as a ban on the drinking of alcohol. It has since been expanded to ban the use of intoxicants. Is tobacco also forbidden under the fifth precept?

user7141: Fifth precept exist because of few reasons. Addictive drugs and beverages are not only unhealthy they are severe distractions for someone on path.
Now let's look at smocking,
First of all i am not a smoker :-) but here is the full story.
As lord Buddha taught there is a thing called dependent arising. Alcohol,cigars,cigarettes,other drugs have a negative effect on the body of the user which effect brain directly and instantly and total health in the long run.Lord Buddha directly said that Health is the true wealth.
Your brain is the center of the thought process and if something happens to your brain you are left with your sub consciousness. That is not how a Buddhist deal with things, we as Buddhist rely on our conscious thoughts (Mindfulness). And as lord Buddha has said beings should not harm their lives and it is bad Karma if you do so. Doing any drug is equal to poisoning yourself slowly to your death, because eventually what happens is that you by conscious choice harm your body which results younger death.
And as we all know smoking is an addiction, There is no taste,comfort or and aid to the body from smoking. There is only the joy of consuming. As Lord Buddha clearly said addictions are bad for the path.

Clearly there is no possible perspective in which addictions like smocking or any other addiction can be justified. If you smoke take time but come out of it never to return.
May triple gems bless you!

user254: There's a Zen story titled, Non-Attachment, which I read as having suggested that it's better to avoid it:

"How pleasant this smoking is ... Such pleasant things may disturb meditation. Before this goes too far, I will stop now." So he threw the smoking outfit away.

Tobacco packaging (in this country) has labelling like, "Smoking Kills" -- so I guess it shouldn't be recommended!
On the other hand, there are some monks who smoke (see Why do Thai monks smoke?), so I guess it's not technically against the five precepts. On the other hand: addiction, eh?
I suppose that nicotine withdrawal causes heedlessness -- so (unless you're willing and able to chain-smoke for the rest of your shortened life) I suspect it isn't recommended and in my opinion is contrary to the spirit of the fifth precept.

user-1: If smoking, as long as not intoxicant things, it does not violate the precept, but since it is most common sense please one goes against what is good in the frame on Dhamma. Yet it is a sense pleasure which causes very less harm for others. Driving for example a car or being after chocolate or burger is over all more harmful. Smoking is somehow the bad child under the really bad and much worthier under the overabundance of sense drugs. 
The point of abstaining from intoxicants is "making one heedless" and so act mostly very unwholsome and unskillful.
To raise the argument that it causes heedlessness it one does not get it, and therefore it is to be seen as causing heedlessness is pointless. If such argument would be valid your woman or you child would be causing even more heedlessness. So that is merely not so well thought. People living indulged in attachments and drugs with cause them permanently heedlessness if not gaining or possible to maintaining the pleasure out of it. 
Surfing in internet or this or that food kill far more, not only one self but a lot of other beings to be provided. There are less "drugs" which are in its hole so less harmful like smoking, yet for sure also harmful especially for ones own health.
Monks are even explicit allowed to smoke pipe and keep certain items for it (MV.VI.13, Mahāvagga VI.01-15 6. Bhesajjakkhandhako). Of course here it seems to have certain health usage.
How ever, is best to let go, if there is a possibility (effort to keep mindfulness arosen, nothing else is needed to abound it) but Atma would see less reason to change ones addiction just to another if it would be not something lesser harmful, the point where Buddhas medicine for certain joy comes in: doing Jhana (meditation) 
At least, one who has touched an amount of liberation will find it more easy to let go of all kind of sensuality.
Matters of Sila and virtue is for sure not not disturbing others with ones smoke and a matter of concern is also not to encourage smoking and if certain addicted to stay ashamed and seclusive when indulging in it.
(Note: this answer has not been given with the agreement to be means of trade or the purpose of/for trade and/or keep people trapped and bound. How you handle it lies in your sphere, but does not excuse the deed here either.)

user7143: Yes smoking is included. 
This document, Five Precepts, says the following about the fifth precept:

There are four conditions
  for the partaking of intoxicants. 
i) There must be an intoxicant.
  ii) There must be the intention of taking it.
  iii) Action must be taken to ingest it.
  iv) There must be actual ingestion of the intoxicant.
Condition (iv) states clearly that the precept is broken once the intoxicant is ingested intentionally. It does not matter whether one is intoxicated or not as a result of the action. 
In taking medicines containing alcohol or intoxicating drugs for medical reasons, no breach of the precept is committed. This is because one's intention is to take the medicine to cure one's sickness.

See also this description, The Five Precepts
pañca-sila:

Suramerayamajja pamadatthana veramani sikkhapadam samadiyami
I undertake the precept to refrain from intoxicating drinks and drugs which lead to carelessness.


user151: I always approached the precepts as very important guidelines rather than rigid rules for banning one's actions. 
Certainly, while on the eightfold path, if one intakes a substance that even subtlety  clouds the mind  then that substance would lead to one's suffering and the suffering of those around one. The more one understands this and the more one sees things as they are, the more one will follow the presepts naturally like a river follows the best way down the side of a  mountain.-Metta

7622: <p>The fifth precept started off as a ban on the drinking of alcohol. It has since been expanded to ban the use of intoxicants. Is tobacco also forbidden under the fifth precept?</p>
 7141: <p>Fifth precept exist because of few reasons. Addictive drugs and beverages are not only unhealthy they are severe distractions for someone on path.</p>

<p>Now let's look at smocking,</p>

<p>First of all i am not a smoker :-) but here is the full story.</p>

<p>As lord Buddha taught there is a thing called dependent arising. Alcohol,cigars,cigarettes,other drugs have a negative effect on the body of the user which effect brain directly and instantly and total health in the long run.Lord Buddha directly said that Health is the true wealth.</p>

<p>Your brain is the center of the thought process and if something happens to your brain you are left with your sub consciousness. That is not how a Buddhist deal with things, we as Buddhist rely on our conscious thoughts (Mindfulness). And as lord Buddha has said beings should not harm their lives and it is bad Karma if you do so. Doing any drug is equal to poisoning yourself slowly to your death, because eventually what happens is that you by conscious choice harm your body which results younger death.</p>

<p>And as we all know smoking is an addiction, There is no taste,comfort or and aid to the body from smoking. There is only the joy of consuming. As Lord Buddha clearly said addictions are bad for the path.</p>

<hr>

<p>Clearly there is no possible perspective in which addictions like smocking or any other addiction can be justified. If you smoke take time but come out of it never to return.</p>

<p>May triple gems bless you!</p>
 254: <p>There's a Zen story titled, <a href="http://www.ashidakim.com/zenkoans/98non-attachment.html" rel="nofollow">Non-Attachment</a>, which I read as having suggested that it's better to avoid it:</p>

<blockquote>
  <p>"How pleasant this smoking is ... Such pleasant things may disturb meditation. Before this goes too far, I will stop now." So he threw the smoking outfit away.</p>
</blockquote>

<p>Tobacco packaging (in this country) has labelling like, "Smoking Kills" -- so I guess it shouldn't be recommended!</p>

<p>On the other hand, there are some monks who smoke (see <a href="http://www.dhammawheel.com/viewtopic.php?t=20222" rel="nofollow">Why do Thai monks smoke?</a>), so I guess it's not technically against the five precepts. On the other hand: addiction, eh?</p>

<p>I suppose that <a href="https://en.wikipedia.org/wiki/Nicotine_withdrawal" rel="nofollow">nicotine withdrawal</a> causes heedlessness -- so (unless you're willing and able to chain-smoke for the rest of your shortened life) I suspect it isn't recommended and in my opinion is contrary to the spirit of the fifth precept.</p>
 -1: <p>If smoking, as long as not intoxicant things, it does not violate the precept, but since it is most common sense please one goes against what is good in the frame on Dhamma. Yet it is a sense pleasure which causes very less harm for others. Driving for example a car or being after chocolate or burger is over all more harmful. Smoking is somehow the bad child under the really bad and much worthier under the overabundance of sense drugs. </p>

<p>The point of abstaining from intoxicants is "making one heedless" and so act mostly very unwholsome and unskillful.</p>

<p>To raise the argument that it causes heedlessness it one does not get it, and therefore it is to be seen as causing heedlessness is pointless. If such argument would be valid your woman or you child would be causing even more heedlessness. So that is merely not so well thought. People living indulged in attachments and drugs with cause them permanently heedlessness if not gaining or possible to maintaining the pleasure out of it. </p>

<p>Surfing in internet or this or that food kill far more, not only one self but a lot of other beings to be provided. There are less "drugs" which are in its hole so less harmful like smoking, yet for sure also harmful especially for ones own health.</p>

<p>Monks are even explicit allowed to smoke pipe and keep certain items for it (MV.VI.13, Mahāvagga VI.01-15 6. Bhesajjakkhandhako). Of course here it seems to have certain health usage.</p>

<p>How ever, is best to let go, if there is a possibility (effort to keep mindfulness arosen, nothing else is needed to abound it) but Atma would see less reason to change ones addiction just to another if it would be not something lesser harmful, the point where Buddhas medicine for certain joy comes in: doing Jhana (meditation) </p>

<p>At least, one who has touched an amount of liberation will find it more easy to let go of all kind of sensuality.</p>

<p>Matters of Sila and virtue is for sure not not disturbing others with ones smoke and a matter of concern is also not to encourage smoking and if certain addicted to stay ashamed and seclusive when indulging in it.</p>

<p><em>(Note: this answer has not been given with the agreement to be means of trade or the purpose of/for trade and/or keep people trapped and bound. How you handle it lies in your sphere, but does not excuse the deed here either.)</em></p>
 7143: <p>Yes smoking is included. </p>

<p>This document, <a href="http://www.urbandharma.org/pdf/PDF_BuddhismCourse/11_%20Five%20Precepts.pdf" rel="nofollow">Five Precepts</a>, says the following about the fifth precept:</p>

<blockquote>
  <p>There are four conditions
  for the partaking of intoxicants. </p>
  
  <p>i) There must be an intoxicant.<br>
  ii) There must be the intention of taking it.<br>
  iii) Action must be taken to ingest it.<br>
  iv) There must be actual ingestion of the intoxicant.</p>
  
  <p>Condition (iv) states clearly that the precept is broken once the intoxicant is ingested intentionally. It does not matter whether one is intoxicated or not as a result of the action. </p>
  
  <p>In taking medicines containing alcohol or intoxicating drugs for medical reasons, no breach of the precept is committed. This is because one's intention is to take the medicine to cure one's sickness.</p>
</blockquote>

<p>See also this description, <a href="http://www.accesstoinsight.org/ptf/dhamma/sila/pancasila.html" rel="nofollow">The Five Precepts
<em>pañca-sila</em></a>:</p>

<blockquote>
  <p><strong>Suramerayamajja pamadatthana veramani sikkhapadam samadiyami</strong></p>
  
  <p>I undertake the precept to refrain from intoxicating drinks and drugs which lead to carelessness.</p>
</blockquote>
 151: <p>I always approached the precepts as very important guidelines rather than rigid rules for banning one's actions. </p>

<p>Certainly, while on the eightfold path, if one intakes a substance that even subtlety  clouds the mind  then that substance would lead to one's suffering and the suffering of those around one. The more one understands this and the more one sees things as they are, the more one will follow the presepts naturally like a river follows the best way down the side of a  mountain.-Metta</p>
