“I allow a double nose-tube” .… “I allow that smoke be inhaled” .… “I allow a tube for inhaling smoke” .… “One should not use fancy smoke-inhaling tubes. Whoever does: an offense of wrong doing. I allow (smoke-inhaling tubes) made of bone,
ivory, horn, reed, bamboo, wood, lac (resin), fruit (§) (e.g., coconut shell), copper (metal), or conch-shell” .… “I allow a lid (for the smoke-inhaling tubes)” .… “I allow a bag for the smoke-inhaling tubes” .… “I allow a double bag” .… “I allow a string for tying the mouth of the bag as a carrying strap.”—Mv.VI.13.1
So smoking as a medical treatment was known.
This is what Ven. Thanissaro has to say in Buddhist Monastic Code I:
There is some controversy as to what other substances would be included in this factor in line with the Great Standards. Because the Canon repeatedly criticizes alcohol on the grounds that it destroys one’s sense of shame, weakens one’s discernment, and can put one into a stupor—as happened to Ven. Sāgata—it seems reasonable to extend this rule to other intoxicants, narcotics, and hallucinogens as well. Thus things like marijuana, hashish, heroin, cocaine, and LSD would fulfill this factor. Coffee, tea, tobacco, and betel do not have this effect, though, so there is no reason to include them here.
My understanding of Sinhala culture is that smoking is seen as particularly evil, and it is especially associated with the evils of western culture.
However chewing betel seems to be no problem at all and is always offered to monks when they visit the home. I’m not so clear as to whether or not tobacco is always included in the gift, even though it is a standard part of the mix.
As I understand, smoking among forest monks in Thailand is quite normal.
@Sanku , welcome to the forum!