diff --git src/wp-includes/meta.php src/wp-includes/meta.php
index 8833d3e..b7ea2af 100644
--- src/wp-includes/meta.php
+++ src/wp-includes/meta.php
@@ -567,12 +567,12 @@ function metadata_exists( $meta_type, $object_id, $meta_key ) {
 function get_metadata_by_mid( $meta_type, $meta_id ) {
 	global $wpdb;
 
-	if ( ! $meta_type || ! is_numeric( $meta_id ) ) {
+	if ( ! $meta_type || ! is_numeric( $meta_id ) || floor( $meta_id ) != $meta_id ) {
 		return false;
 	}
 
-	$meta_id = absint( $meta_id );
-	if ( ! $meta_id ) {
+	$meta_id = intval( $meta_id );
+	if ( $meta_id <= 0 ) {
 		return false;
 	}
 
@@ -611,12 +611,12 @@ function update_metadata_by_mid( $meta_type, $meta_id, $meta_value, $meta_key =
 	global $wpdb;
 
 	// Make sure everything is valid.
-	if ( ! $meta_type || ! is_numeric( $meta_id ) ) {
+	if ( ! $meta_type || ! is_numeric( $meta_id ) || floor( $meta_id ) != $meta_id ) {
 		return false;
 	}
 
-	$meta_id = absint( $meta_id );
-	if ( ! $meta_id ) {
+	$meta_id = intval( $meta_id );
+	if ( $meta_id <= 0 ) {
 		return false;
 	}
 
@@ -702,12 +702,12 @@ function delete_metadata_by_mid( $meta_type, $meta_id ) {
 	global $wpdb;
 
 	// Make sure everything is valid.
-	if ( ! $meta_type || ! is_numeric( $meta_id ) ) {
+	if ( ! $meta_type || ! is_numeric( $meta_id ) || floor( $meta_id ) != $meta_id ) {
 		return false;
 	}
 
-	$meta_id = absint( $meta_id );
-	if ( ! $meta_id ) {
+	$meta_id = intval( $meta_id );
+	if ( $meta_id <= 0 ) {
 		return false;
 	}
 
diff --git tests/phpunit/tests/meta.php tests/phpunit/tests/meta.php
index 0676c7e..eb6f2c5 100644
--- tests/phpunit/tests/meta.php
+++ tests/phpunit/tests/meta.php
@@ -293,6 +293,44 @@ class Tests_Meta extends WP_UnitTestCase {
 	}
 
 	/**
+	 * @ticket 37746
+	 */
+	function test_negative_meta_id() {
+		$negative_mid = $this->meta_id * -1;
+
+		$this->assertTrue( $negative_mid < 0 );
+		$this->assertFalse( get_metadata_by_mid( 'user', $negative_mid ) );
+		$this->assertFalse( update_metadata_by_mid( 'user', $negative_mid, 'meta_new_value' ) );
+		$this->assertFalse( delete_metadata_by_mid( 'user', $negative_mid ) );
+	}
+
+	/**
+	 * @ticket 37746
+	 */
+	function test_floating_meta_id() {
+		$floating_mid = $this->meta_id + 0.1337;
+
+		$this->assertTrue( floor( $floating_mid ) !== $floating_mid );
+		$this->assertFalse( get_metadata_by_mid( 'user', $floating_mid ) );
+		$this->assertFalse( update_metadata_by_mid( 'user', $floating_mid, 'meta_new_value' ) );
+		$this->assertFalse( delete_metadata_by_mid( 'user', $floating_mid ) );
+	}
+
+	/**
+	 * @ticket 37746
+	 */
+	function test_string_point_zero_meta_id() {
+		$meta_id = add_metadata( 'user', $this->author->ID, 'meta_key', 'meta_value_2' );
+
+		$string_mid = "{$meta_id}.0";
+
+		$this->assertTrue( floor( $string_mid ) == $string_mid );
+		$this->assertNotEquals( false, get_metadata_by_mid( 'user', $string_mid ) );
+		$this->assertNotEquals( false, update_metadata_by_mid( 'user', $string_mid, 'meta_new_value_2' ) );
+		$this->assertNotEquals( false, delete_metadata_by_mid( 'user', $string_mid ) );
+	}
+
+	/**
 	 * @ticket 15030
 	 */
 	public function test_get_metadata_with_empty_key_array_value() {