diff --git a/library/std/src/sync/mutex.rs b/library/std/src/sync/mutex.rs
index 895fcbd6b7ed8..d417034f5af85 100644
--- a/library/std/src/sync/mutex.rs
+++ b/library/std/src/sync/mutex.rs
@@ -396,7 +396,7 @@ impl<T: ?Sized> Mutex<T> {
         self.poison.get()
     }
 
-    /// Clear the poisoned state from a mutex
+    /// Clear the poisoned state from a mutex.
     ///
     /// If the mutex is poisoned, it will remain poisoned until this function is called. This
     /// allows recovering from a poisoned state and marking that it has recovered. For example, if
diff --git a/library/std/src/sync/rwlock.rs b/library/std/src/sync/rwlock.rs
index f7f098c082a0f..d648cd089943f 100644
--- a/library/std/src/sync/rwlock.rs
+++ b/library/std/src/sync/rwlock.rs
@@ -439,7 +439,7 @@ impl<T: ?Sized> RwLock<T> {
         self.poison.get()
     }
 
-    /// Clear the poisoned state from a lock
+    /// Clear the poisoned state from a lock.
     ///
     /// If the lock is poisoned, it will remain poisoned until this function is called. This allows
     /// recovering from a poisoned state and marking that it has recovered. For example, if the