The answer to 'bathtub making gurgling noise' is that a gurgling sound in the bathtub is often caused by a clogged drain or a vent pipe issue. This can happen when hair, soap scum, and other debris build up in the drain, causing water to back up and air to be forced back up through the drain, creating the gurgling sound.
Some common symptoms of a gurgling bathtub include slow draining, water backing up, and foul odors coming from the drain. Solutions can include using a plunger or drain snake to clear the clog, or checking the vent pipe to ensure it is not blocked. If the issue persists, it's best to call a professional plumber to diagnose and fix the problem.