Exchanging passionate kisses with big-screen star Jennifer Lawrence might sound like a dream come true. But according to Liam Hemsworth, her Hunger Games co-star, it could also be a nightmare… because J.Law’s breath wasn’t always fresh. “Anytime I had to kiss Jennifer was pretty uncomfortable,” Hemsworth said on The Tonight Show.

Lawrence said the problem resulted from her inadvertently consuming tuna or garlic before the lip-locking scenes; fortunately, the two stars were able to share a laugh about it later. But for many people, bad breath is no joke. It can lead to embarrassment and social difficulties — and it occasionally signifies a more serious problem. So what causes bad breath, and what can you do about it?

In 9 out of 10 cases, bad breath originates in the mouth. (In rare situations, it results from a medical issue in another part of the body, such as liver disease or a lung infection.) The foul odors associated with bad breath can be temporarily masked with mouthwash or breath mints — but in order to really control it, we need to find out exactly what’s causing the problem, and address its source.

As Lawrence and Hemsworth found out, some foods and beverages can indeed cause a malodorous mouth. Onions, garlic, alcohol and coffee are deservedly blamed for this. Tobacco products are also big contributors to bad breath — which is one more reason to quit. But fasting isn’t the answer either: stop eating for long enough and another set of foul-smelling substances will be released. Your best bet is to stay well hydrated and snack on crisp, fresh foods like celery, apples or parsley.

And speaking of hydration (or the lack of it): Mouth dryness and reduced salivary flow during the nighttime hours is what causes “morning breath.” Certain health issues and some medications can also cause “dry mouth,” or xerostomia. Drinking plenty of water can encourage the production of healthy saliva — but if that’s not enough, tell us about it: We may recommend switching medications (if possible), chewing xylitol gum or using a saliva substitute.

Finally, maintaining excellent oral hygiene is a great way to avoid bad breath. The goal of oral hygiene is to control the harmful bacteria that live in your mouth. These microorganisms can cause gum disease, tooth decay, and bad breath — so keeping them in check is good for your overall oral health. Remember to brush twice and floss once daily, stay away from sugary foods and beverages, and visit the dental office regularly for checkups and professional cleanings.

So did J.Law apologize for the malodorous makeout session? Not exactly. “[For] Bradley Cooper, Christian Bale, yeah, I’ll brush my teeth,” she laughed.

Hemsworth jokingly agreed: “If I was kissing Christian Bale I probably would have brushed my teeth too. With you, it’s like, ‘Eh. Whatever.’”

If you would like more information about bad breath and oral hygiene, please contact us or schedule an appointment for a consultation. You can learn more by reading the Dear Doctor magazine article “Bad Breath: More than Just Embarrassing.”

Unlike the months on either side, August isn't known for major holidays. But it does have one cause for celebration: National Fresh Breath Day! True, this observance will probably never achieve big-time recognition. Yet everyone would agree that fresh breath is something to appreciate! Unfortunately, bad breath is a persistent problem for many people. The first step in treating it is to identify the cause. Here are 5 common causes of bad breath:

1. Poor oral hygiene. Certain types of oral bacteria cause bad breath, and the mouth provides a perfect environment for them—especially when dental plaque and food debris is not well cleansed. So to keep your breath fresh, maintain a diligent oral hygiene routine. This includes brushing your teeth twice a day with fluoride toothpaste and flossing at least once a day. For an extra-clean mouth, use a tongue scraper—a plastic tool about the size of a toothbrush that's available in most drug stores. This will remove bacteria and food debris from your tongue for extra freshness.

2. Oral diseases. Bad odors in your mouth may also be caused by infections—which is what tooth decay and gum disease actually are. Sometimes old fillings wear out, allowing bacteria to re-infect a tooth that was once treated for decay. Other signs of these common oral diseases include tooth pain and bleeding or puffy gums. If you notice any of these, don't ignore it—make a dental appointment today!

3. Diet. Smelly foods will give you smelly breath; it's that simple. And the odors may linger after you have eaten them. When onion, garlic and other pungent foods are digested, their odor-producing substances enter your bloodstream and proceed to your lungs—which can affect how your breath smells. If you suspect your dietary habits are causing bad breath, try eliminating certain foods (at least temporarily) and see if that helps.

4. Dry mouth. Saliva helps cleanse your mouth, so reduced saliva flow can lead to bad breath. This accounts for "morning breath," which is caused when the mouth dries out during sleep (especially if you are a mouth-breather). However, some people don't produce enough saliva throughout the day. Sometimes it's just that they don't drink enough water. But a very common cause of chronic dry mouth is regular use of medications, both prescription and over-the-counter. If you notice that medication is drying out your mouth, let your doctor know. And stay hydrated!

5. Smoking. Given that smoking increases your risk for many serious diseases, including oral cancer, the fact that it can lead to bad breath seems almost trivial. Still, it's worth noting that smoking causes mouth odor both directly and indirectly by reducing the flow of saliva and promoting gum disease. In fact, tobacco in all forms is a hazard to your health.

If you'd like more information on bad breath, please contact us or schedule an appointment for a consultation. You can learn more in the Dear Doctor magazine articles “Warning Signs of Periodontal (Gum) Disease” and “Dry Mouth.”