diff --git a/ext/mdbx_ext/database.c b/ext/mdbx_ext/database.c
index 8506204..38e1c2a 100644
--- a/ext/mdbx_ext/database.c
+++ b/ext/mdbx_ext/database.c
@@ -45,19 +45,36 @@ static const rb_data_type_t rmdbx_db_data = {
 VALUE
 rmdbx_alloc( VALUE klass )
 {
-	int *data = malloc( sizeof(rmdbx_db_t) );
-	return TypedData_Wrap_Struct( klass, &rmdbx_db_data, data );
+	rmdbx_db_t *data;
+	return TypedData_Make_Struct( klass, rmdbx_db_t, &rmdbx_db_data, data );
+}
+
+
+/*
+ * Ensure all database file descriptors are collected and
+ * removed.
+ */
+void
+rmdbx_destroy( rmdbx_db_t* db )
+{
+	if ( db->cursor ) mdbx_cursor_close( db->cursor );
+	if ( db->txn )    mdbx_txn_abort( db->txn );
+	if ( db->dbi )    mdbx_dbi_close( db->env, db->dbi );
+	if ( db->env )    mdbx_env_close( db->env );
+	db->open = 0;
 }
 
 
 /*
  * Cleanup a previously allocated DB environment.
- * FIXME:  ... this should also close if not already closed?
  */
 void
 rmdbx_free( void *db )
 {
-	if ( db ) free( db );
+	if ( db ) {
+		rmdbx_destroy( db );
+		free( db );
+	}
 }
 
 
@@ -68,14 +85,7 @@ VALUE
 rmdbx_close( VALUE self )
 {
 	UNWRAP_DB( self, db );
-	if ( db->cursor ) mdbx_cursor_close( db->cursor );
-	if ( db->txn )    mdbx_txn_abort( db->txn );
-	if ( db->dbi )    mdbx_dbi_close( db->env, db->dbi );
-	if ( db->env )    mdbx_env_close( db->env );
-	db->open = 0;
-
-	// FIXME: or rather, maybe free() from here?
-
+	rmdbx_destroy( db );
 	return Qtrue;
 }
 
diff --git a/spec/mdbx/database_spec.rb b/spec/mdbx/database_spec.rb
index d05d7ee..d636eb6 100644
--- a/spec/mdbx/database_spec.rb
+++ b/spec/mdbx/database_spec.rb
@@ -17,5 +17,25 @@ RSpec.describe( MDBX::Database ) do
 		expect( db.closed? ).to be_truthy
 	end
 
+	context 'an opened database' do
+
+		before( :each ) do
+			@db = described_class.open( TEST_DATABASE.to_s )
+		end
+
+		after( :each ) do
+			@db.close
+		end
+
+		it "fails if opened again within the same process" do
+			# This is a function of libmdbx internals, just testing
+			# here for behaviorals.
+			expect {
+				described_class.open( TEST_DATABASE.to_s )
+			}.
+			to raise_exception( MDBX::DatabaseError, /environment is already used/ )
+		end
+
+	end
 end