Reflexive pronouns: accusative vs. dative (mich vs. mir)
When a reflexive verb's action falls on the whole person you use the accusative; when there's already a direct object, the reflexive pronoun switches to the dative.
A reflexive pronoun points the action back at the subject. For most persons it looks like the accusative pronoun (mich, dich, uns, euch), and in the 3rd person it is always sich.
The case depends on what else is in the sentence:
- No other object → accusative: the whole person is affected. Ich wasche mich. (I wash.)
- A direct object is already present → dative: typically a body part or thing. The reflexive steps back to the dative. Ich wasche mir die Hände. (I wash my hands.)
Only the 1st and 2nd person singular actually change form (mich → mir, dich → dir); the rest are identical in both cases. So the whole trick is: name a direct object, and the reflexive goes dative.
Examples
Ich wasche mich.
I wash (myself).
Ich wasche mir die Hände.
I wash my hands.
Common mistakes
Once there is a direct object (die Hände), the reflexive pronoun must be dative: mir, not mich.