Why intake of intoxicating substances is not included in 10 unwholesome actions?

Everybody is intoxicated. Some people to food, some to sex, some to power, some to alcohol. Buddha never said anything about sex, food, alcohol or other intoxicants. Sexual conduct is only defined for monks. Buddha never said anything about householders. Meditation alone is the cure for intoxication of any kind. Please remember Buddha's path is path of intelligence. Any intelligent person will see an intoxicant as bondage and will set himself free of it. There is no need for any Sutta.

The Unwholesome actions produce a karmic seed that will definitely fruit.

For example, even if you killed someone out of self-defense, there would be a negative result.

Even if you got angry towards someone because they are harming themselves, you would produce a negative karmic seed.

That is why these are "unwholesome" fundamentally.

Many things that produce an un-sober state on the other hand only do so after a certain point. There are many medical situations where it is necessary. Many medicines have alcohol as an agent. The same goes for other inebriating drugs. It is of course better to avoid them altogether but there is no diet that is fundamentally unwholesome.

On the other hand, the unwholesome actions are on some fundamental level going to cause some karmic repercussion.

First of all, the Buddha never talks about drugs as such. He talks about alcohol, including a form of alcohol that was used in Ayurvedic medicine as an anesthetic, i.e., a drug, but the Pali suttas do not include any words that can be directly translated as "drugs." Alcohol is frequently absent from lists of prohibited activities, including the famous Pansil, i.e., Five Precepts. There is a fourfold version of pansil called the Four Restraints. As to why this is the case, the answer is that it is because the Buddha did not prohibit alcohol for the first eight years of the sangha. The Buddha only prohibited alcohol when a monk got drunk and passed out, embarassing the sangha. This happened during a famine, when all that the villagers had to offer the monastics was palm wine. Subsequently drinking alcohol was added to the Four Restraints to make the Five Precepts, and the Buddha forbade the ordination of drinkers, but at the same time drinking alcohol is a very minor offence in the Vinaya, requiring confession only.

Buddha told Ven Sariputta that he would not answer to any questions or teach anything that might promote heedlessness. So here is strictly my opinion. Perhaps there is threshold of consuming alcohol or intoxicants?? For example, if one uses cooking wine to prepare a dish for its aroma, would that consider breaking a precept? What about fermented rice for desert (yeast+rice+sugar)? It has slight alcohol in it but not enough to alter mind. Again, my opinion, there could be a possible threshold of consuming intoxicant but mentioning it would promote heedlessness. It could possibly be that there is some qualifier in the 5th precept that is best not to mention? Best not to consume it at all.

• Saleyyaka Sutta mention 10 without intake of intoxicants
• Veludvāreyya Sutta mention 7 without intake of intoxicants
• Sigal’ovada Sutta mention 4 without intake of intoxicants (this is mentioned separately though)

Once I heard that in early Indian kings use to take a drink in the evening. The Buddha was careful not to introduce this precept in early day of his teaching until most of the Kings, ministers and tycoons where his disciples. Later when this happened this was introduced. If this was prematurely introduced many who were taking habitual or customary drinks might not have been inclined to listen to the Dhamma. This is just a theory to explain the lack intake of intoxicants in some Suttas some which were early days of the dispensation.