Poisoned: which rolls are affected?

SRD 5.2.1 · Conditions

At the table

1. Apply Disadvantage to attack rolls.
2. Apply Disadvantage to ability checks.
3. Check the originating effect for damage, saves, duration and removal; do not invent those details from the condition name.

Example decision

A Poisoned character makes a Dexterity saving throw against a trap. Does Poisoned alone give that saving throw Disadvantage?

No; the condition names attack rolls and ability checks, not saving throws.

A saving throw is not an ability check. Poisoned therefore does not, by itself, impose Disadvantage on this Dexterity save. A separate effect might modify that save, so check the full situation. The character’s next attack roll or ability check is affected by Poisoned, subject to the normal interaction of Advantage and Disadvantage.

Watch for this mistake

Poison damage and the Poisoned condition are separate game effects. An effect can deal Poison damage without imposing this condition, or impose the condition under its own specified terms. Never infer one solely from the other’s name.

Ask the table

Is this roll an attack, an ability check or a saving throw, and what does the source effect separately require?

Source rule

While you have the Poisoned condition, you experience the following effect. Ability Checks and Attacks Affected. You have Disadvantage on attack rolls and ability checks.

Source: SRD 5.2.1, 186. Online guide.