BY MICHAEL ROIZEN, M.D., AND MEHMET OZ, M.D.

Whether it's over a tearjerker movie, a sweet note from your spouse or a lethal parking ticket, go ahead and cry. Tears are good for you: Just as sweat removes salt, urine removes waste and mucus traps bacteria, tears have a purpose, too.

Emotional tears, shed in moments of intense feeling, do more than keep the Kleenex folks in business. They also carry stress hormones and are a way of getting rid of them. Needing to cry also signals that you've reached a level of stress that's detrimental to your health.

But here's the really amazing thing: Emotional tears are just one of three types of good-for-you tears your body makes, and each is chemically different from the other two:

Basal tears are produced continuously to keep your eyes lubricated. That layer of moisture also helps prevent damage from air currents and bits of floating debris.

Irritant tears are produced when flying sand, grit, insects, etc., find their way to your eyes and need to be flushed out. They help prevent damage to your eyes from these low-flyers.

Emotional tears are released in moments of intense feeling and help wash away stress hormones.

Discounting a few unverified tales of weepy gorillas and elephants (which may, someday, prove to be accurate), it seems humans are the only ones to cry. When you do it, don't hide it from your friends; showing your vulnerability to them can help soothe the adverse effects of stress.

The YOU Docs, Mehmet Oz and Mike Roizen, are authors of "YOU: The Owner's Manual." Want more? See "The Dr. Oz Show" on TV starting Sept. 14 (check local listings). To submit questions, go to www.RealAge.com.