When no food is in the system, the muscles force down whatever gas and liquid remain, producing the rumbling effect. But rumbling doesn't necessarily end when your stomach's full. Digesting a high-fiber meal can generate the grumbles as well, as can stress and caffeine. Rumbling is rarely cause for alarm, but if the noises are persistent or accompanied by pain, you may have an ulcer or a gallbladder problem. If this is the case, seek medical attention.
Most people suffer from periodic but brief episodes of tinnitus, commonly called ear ringing.
Temporary tinnitus is caused by a fatigued inner ear, the result of earwax buildup, infection, high blood pressure, diabetes, smoking, or simply getting older. Temporary tinnitus is nothing to worry about, but if the ringing persists or is accompanied by pain or dizziness, see your doctor. Prolonged exposure to loud noise can damage the inner-ear structure, causing chronic tinnitus. Despite what you may have heard, knuckle cracking does not harm the joints or cause arthritis. Cracking the knuckles simply snaps the ligament across the bones and releases pressure in the capsules between the joints, producing the cracking sound.