Alterum non laedere
“Do not harm another.”
Ulpian, Digest 1.1.10
What does “Alterum non laedere” mean?
Alterum non laedere translates as “Do not harm another.”
One of the basic duties of law and ethics: do no injury to others. It sums up the minimum we owe every person.
“Alterum non laedere” word by word
| Latin | English | Grammar |
|---|---|---|
| Alterum | another (person) | accusative singular masculine of alter, “the other, another”; the direct object of laedere |
| non | not | adverb of negation; here it negates the infinitive |
| laedere | to harm | present infinitive active of laedo, “I harm, I injure” |
How to pronounce “Alterum non laedere”
The difference is the ae in laedere: Classical “eye” (LAI-deh-reh), Church “eh” (LEH-deh-reh). Stress falls on the first syllable of alterum and of laedere.
The story behind it
Word for word the phrase reads “not to harm another”. In legal Latin it works as a rule: do not injure other people.
It comes from the Roman jurist Ulpian, whose words are preserved in the Digest (1.1.10), the great collection of Roman legal writings assembled under the emperor Justinian in the sixth century AD. There Ulpian lists three basic precepts of law: honeste vivere (to live honestly), alterum non laedere (not to harm another), and suum cuique tribuere (to give each his own).
Later European lawyers took the formula as a basic principle of private law and of liability for causing harm. It is still quoted in discussions of law and ethics.
How to use “Alterum non laedere”
A fitting heading for a code of conduct, a law student’s notebook or an essay on duty and responsibility. It also works as a short personal motto for someone who wants to put ethics first.
- Latin
- Alterum non laedere
- English
- Do not harm another.
- Source
- Ulpian, Digest 1.1.10
- Era
- Legal Latin
- Theme
- Justice
Common mistakes
- It is not a command to do good. It sets the minimum, not harming others, and says nothing about helping them.
- It is one of three precepts in Ulpian’s list. Quoting it alone is fine, but it is not his whole definition of justice.
- Alterum is masculine accusative singular, so it is used here for “another person”. It does not change for a woman as the object: alter is also used for the other person generally, but do not alter the endings without checking.
- Spelling: it is laedere with ae, not ledere or laidere.
Questions about “Alterum non laedere”
What does “Alterum non laedere” mean literally?
“Not to harm another.” It is an infinitive phrase, usually rendered as “Do not harm another”.
Who said “Alterum non laedere”?
The Roman jurist Ulpian, in a passage preserved in Justinian’s Digest (1.1.10), where it is one of three precepts of law.
How do you pronounce “Alterum non laedere”?
Classical: AL-teh-room nohn LAI-deh-reh. Church Latin: AL-teh-room nohn LEH-deh-reh.
What are Ulpian’s three precepts of law?
Honeste vivere (live honestly), alterum non laedere (do not harm another) and suum cuique tribuere (give each his due).
More to explore
Translation and grammar checked by Latin Quoter · last reviewed November 2026
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