diff --git a/.worktrees/backport-2.x b/.worktrees/backport-2.x
new file mode 160000
index 000000000..3b93dec2d
--- /dev/null
+++ b/.worktrees/backport-2.x
@@ -0,0 +1 @@
+Subproject commit 3b93dec2dc5e995398fb45f5466bf96fc0bd0c7d
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 311cc5a64..a9336fb58 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -45,6 +45,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 - Added missing types for AwsSigv4SignerOptions.service ([#377](https://github.com/opensearch-project/opensearch-js/pull/377))
 - Fixed deprecated folder mapping "./" in the "exports" field module resolution ([#416](https://github.com/opensearch-project/opensearch-js/pull/416))
+- Fixed `BaseConnectionPool` markAlive and markDead and their tests ([#449](https://github.com/opensearch-project/opensearch-js/pull/449))
 
 ### Security
 
diff --git a/USER_GUIDE.md b/USER_GUIDE.md
index 579c170e3..91aa047a2 100644
--- a/USER_GUIDE.md
+++ b/USER_GUIDE.md
@@ -249,4 +249,74 @@ console.log('Deleting all PITs:');
 var response = await client.deleteAllPits();
 
 console.log(response.body);
+```
+
+## Mark connection as `dead`
+```javascript
+console.log('Marking connection as dead:');
+
+var connection = client.connectionPool.getConnection()
+// or var connection = client.connectionPool.connections[0]
+
+if (connection !== null) {
+  client.connectionPool.markDead(connection)
+}
+```
+
+## Mark connection as `alive`
+```javascript
+console.log('Marking connection as alive:');
+
+var connection = client.connectionPool.getConnection()
+// or var connection = client.connectionPool.connections[0]
+
+if (connection !== null) {
+  client.connectionPool.markAlive(connection)
+}
+```
+## Mark connection as `dead`
+```javascript
+console.log('Marking connection as dead:');
+
+var connection = client.connectionPool.getConnection()
+// or var connection = client.connectionPool.connections[0]
+
+if (connection !== null) {
+  client.connectionPool.markDead(connection)
+}
+```
+
+## Mark connection as `alive`
+```javascript
+console.log('Marking connection as alive:');
+
+var connection = client.connectionPool.getConnection()
+// or var connection = client.connectionPool.connections[0]
+
+if (connection !== null) {
+  client.connectionPool.markAlive(connection)
+}
+```
+## Mark connection as `dead`
+```javascript
+console.log('Marking connection as dead:');
+
+var connection = client.connectionPool.getConnection()
+// or var connection = client.connectionPool.connections[0]
+
+if (connection !== null) {
+  client.connectionPool.markDead(connection)
+}
+```
+
+## Mark connection as `alive`
+```javascript
+console.log('Marking connection as alive:');
+
+var connection = client.connectionPool.getConnection()
+// or var connection = client.connectionPool.connections[0]
+
+if (connection !== null) {
+  client.connectionPool.markAlive(connection)
+}
 ```
\ No newline at end of file
diff --git a/lib/pool/BaseConnectionPool.js b/lib/pool/BaseConnectionPool.js
index c2a901f64..29dab490f 100644
--- a/lib/pool/BaseConnectionPool.js
+++ b/lib/pool/BaseConnectionPool.js
@@ -52,11 +52,13 @@ class BaseConnectionPool {
     throw new Error('getConnection must be implemented');
   }
 
-  markAlive() {
+  markAlive(connection) {
+    connection.status = Connection.statuses.ALIVE;
     return this;
   }
 
-  markDead() {
+  markDead(connection) {
+    connection.status = Connection.statuses.DEAD;
     return this;
   }
 
diff --git a/test/unit/base-connection-pool.test.js b/test/unit/base-connection-pool.test.js
index 8af26a393..059dfca3d 100644
--- a/test/unit/base-connection-pool.test.js
+++ b/test/unit/base-connection-pool.test.js
@@ -76,7 +76,18 @@ test('API', (t) => {
     let connection = pool.addConnection(href);
     t.same(pool.markDead(connection), pool);
     connection = pool.connections.find((c) => c.id === href);
-    t.equal(connection.status, Connection.statuses.ALIVE);
+    t.equal(connection.status, Connection.statuses.DEAD);
+    t.end();
+  });
+
+  t.test('call markDead twice', (t) => {
+    const pool = new BaseConnectionPool({ Connection, sniffEnabled: true });
+    const href = 'http://localhost:9200/';
+    let connection = pool.addConnection(href);
+    t.same(pool.markDead(connection), pool);
+    t.same(pool.markDead(connection), pool);
+    connection = pool.connections.find((c) => c.id === href);
+    t.equal(connection.status, Connection.statuses.DEAD);
     t.end();
   });
 
@@ -90,6 +101,31 @@ test('API', (t) => {
     t.end();
   });
 
+  t.test('call markAlive twice', (t) => {
+    const pool = new BaseConnectionPool({ Connection, sniffEnabled: true });
+    const href = 'http://localhost:9200/';
+    let connection = pool.addConnection(href);
+    t.same(pool.markAlive(connection), pool);
+    t.same(pool.markAlive(connection), pool);
+    connection = pool.connections.find((c) => c.id === href);
+    t.equal(connection.status, Connection.statuses.ALIVE);
+    t.end();
+  });
+
+  t.test('call markDead and markAlive', (t) => {
+    const pool = new BaseConnectionPool({ Connection, sniffEnabled: true });
+    const href = 'http://localhost:9200/';
+    let connection = pool.addConnection(href);
+    t.same(pool.markDead(connection), pool);
+    t.equal(connection.status, Connection.statuses.DEAD);
+    t.same(pool.markAlive(connection), pool);
+    t.equal(connection.status, Connection.statuses.ALIVE);
+    connection = pool.connections.find((c) => c.id === href);
+    t.equal(connection.status, Connection.statuses.ALIVE);
+    t.not(connection.status, Connection.statuses.DEAD);
+    t.end();
+  });
+
   t.test('getConnection should throw', (t) => {
     const pool = new BaseConnectionPool({ Connection });
     const href = 'http://localhost:9200/';