MANILA -- Kissing has always been a way of showing love and affection between two people. But having a bad breath can ruin everything.

In DZMM's Private Nights, Dr. Lulu Marquez explained that having bad breath, medically called halitosis, can interfere with intimacy and make it more difficult to share certain experiences that make relationships special.

According to Marquez, bad breath is usually caused by bacteria that coat the teeth and gums. It can also result from poor oral hygiene or even a sign of other health problems.

• READ: When bad breath is more than just an oral problem

There are five common causes of bad breath or halitosis.

1. Tooth and gum problems

Bits of food that get stuck between the teeth and on the tongue will rot, leaving an unpleasant odor. Also, strong foods like garlic and onions can add to the problem.

If you don't brush and floss every day, food stays in the mouth and collects bacteria, which can cause bad breath. "Ideally you should brush your teeth twice a day," Marquez said.

2. Poor digestion in stomach and intestine.

If there is bad breath with no presence of tooth decay, it may be associated with poor digestion. Digestive system disorders, such as reflux, can also cause foul-smelling breath. "It is important to eat slowly for proper digestion," she said.

3. An unhealthy liver

An unhealthy liver can also be the cause of bad breath. You will know this if you've ever smelled the breath of someone with a hangover.

4. Sinus infections

Sometimes bad breath originates from infections in the sinuses, which drip infected mucus down the back of the throat. The infected mucus enters the stomach and typically there is insufficient stomach acid to kill the bacteria.

5. Dry mouth

Saliva contains antimicrobial substances, and it helps wash away excessive bacteria from your teeth and gums.

If you don't produce enough saliva, bacteria can multiply in much greater quantities and release toxins that can harm the teeth and gums. "Drinking more water is one way to manage it," Marquez advised.

Bad breath is much more than just an embarrassment. So, don't let bad breath cause the kiss of death in your relationship.