diff --git a/substrate/client/cli/src/params/pruning_params.rs b/substrate/client/cli/src/params/pruning_params.rs
index fa30aa53b8..9d471224cc 100644
--- a/substrate/client/cli/src/params/pruning_params.rs
+++ b/substrate/client/cli/src/params/pruning_params.rs
@@ -33,6 +33,8 @@ pub struct PruningParams {
 	/// Specify the number of finalized blocks to keep in the database.
 	///
 	/// Default is to keep all blocks.
+	///
+	/// NOTE: only finalized blocks are subject for removal!
 	#[clap(long, value_name = "COUNT")]
 	pub keep_blocks: Option<u32>,
 }
diff --git a/substrate/client/db/src/lib.rs b/substrate/client/db/src/lib.rs
index 5f15b2d6fe..ccdb434dfb 100644
--- a/substrate/client/db/src/lib.rs
+++ b/substrate/client/db/src/lib.rs
@@ -302,6 +302,8 @@ pub struct DatabaseSettings {
 	/// Where to find the database.
 	pub source: DatabaseSource,
 	/// Block pruning mode.
+	///
+	/// NOTE: only finalized blocks are subject for removal!
 	pub keep_blocks: KeepBlocks,
 }
 
diff --git a/substrate/client/network/test/src/lib.rs b/substrate/client/network/test/src/lib.rs
index 9e23a4cc67..9e752e81a3 100644
--- a/substrate/client/network/test/src/lib.rs
+++ b/substrate/client/network/test/src/lib.rs
@@ -667,6 +667,8 @@ impl<B: BlockT> warp_request_handler::WarpSyncProvider<B> for TestWarpSyncProvid
 #[derive(Default)]
 pub struct FullPeerConfig {
 	/// Pruning window size.
+	///
+	/// NOTE: only finalized blocks are subject for removal!
 	pub keep_blocks: Option<u32>,
 	/// Block announce validator.
 	pub block_announce_validator: Option<Box<dyn BlockAnnounceValidator<Block> + Send + Sync>>,
diff --git a/substrate/client/service/src/config.rs b/substrate/client/service/src/config.rs
index c895300fea..0eeb6e05ce 100644
--- a/substrate/client/service/src/config.rs
+++ b/substrate/client/service/src/config.rs
@@ -77,6 +77,8 @@ pub struct Configuration {
 	/// State pruning settings.
 	pub state_pruning: Option<PruningMode>,
 	/// Number of blocks to keep in the db.
+	///
+	/// NOTE: only finalized blocks are subject for removal!
 	pub keep_blocks: KeepBlocks,
 	/// Chain configuration.
 	pub chain_spec: Box<dyn ChainSpec>,