Section 66 — Intoxication as an excuse
English translation
Intoxication caused by the consumption of liquor or other intoxicants cannot be raised as an excuse under Section 65, unless the intoxication occurred without the doer's knowledge or against his will and rendered him unable to appreciate right and wrong or unable to control himself, in which case the doer shall be exempt from punishment.
But if the doer still retains some ability to appreciate right and wrong, or still retains some ability to control himself, the Court may inflict a punishment less than that provided by law for such offence to any extent.
This English translation is provided for reference only and has not yet been firm-verified — always rely on the Thai original.
Firm annotation
Section 66 qualifies the insanity excuse in Section 65 for cases of intoxication. The general rule is that self-induced intoxication is no excuse: a person who voluntarily consumes liquor or drugs cannot claim inability to appreciate right and wrong or to control himself. The narrow exception is involuntary intoxication, either without the doer's knowledge or by coercion, that produced total incapacity, which exempts from punishment; where only partial incapacity resulted, the court may reduce below the statutory minimum to any extent. The provision sits alongside Section 65 in Book 1 and turns on whether the intoxication was voluntary, so the manner in which the substance was taken is the decisive fact. It should not be confused with the Narcotics Act, which uses its own separately numbered provisions.
Why this matters in practice
For a defendant who was drunk or high at the time of the offence, Section 66 almost always closes the door: voluntary intoxication is not a defence and does not negate liability, so being intoxicated will not by itself defeat a finding of intent. The exception is genuinely narrow and requires proof that the intoxication was involuntary, imposed without knowledge or by force, and severe enough to destroy capacity. Where intoxication was voluntary but partial incapacity is shown, the realistic benefit is mitigation, not acquittal. Anyone charged with a serious offence committed while intoxicated should get criminal law advice on whether any part of Section 66 is arguable.
Supreme Court decisions interpreting this section
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Supreme Court Judgment No. 5923/2559 (2016)
A person who voluntarily drinks alcohol knowing it causes intoxication cannot invoke that intoxication under Section 66 to claim inability to appreciate right and wrong or control himself.
The defendant entered a pub and drank, which the Court held to be voluntary consumption knowing it causes intoxication. He therefore could not raise the intoxication as an excuse under Section 66, and was held to have intended to kill, supporting the attempted murder conviction.
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Supreme Court Judgment No. 6445/2537 (1994)
Even where an offence is committed while intoxicated by liquor, the doer cannot raise the intoxication as an excuse to avoid punishment under Section 66.
The defendant fired a gun, killing one person and wounding another. The Court held that even accepting he acted while intoxicated by liquor, he could not raise that intoxication as an excuse to escape punishment under Section 66, and remained liable for murder and attempted murder.
Curated decisions with case numbers verified against the Supreme Court database. English renderings are the firm's editorial translation for study.
Frequently asked questions
Can I use being drunk as a defence to a crime?
No, if you drank voluntarily. Section 66 provides that self-induced intoxication cannot be raised as an excuse under Section 65, so voluntary drunkenness will not negate liability.
When does intoxication exempt someone from punishment?
Only where the intoxication occurred without the person's knowledge or against his will and made him unable to appreciate right and wrong or control himself. If some ability remained, the court may only reduce the punishment.