The home remedies for bad breath include clove, hazelnut, lemon, parsley, mint, basil, cardamom, fennel seeds, cinnamon, apple, carrot, pears, mint, wintergreen, apple cider vinegar, tea of parsley and myrrh, and baking soda.
Bad breath is one where a foul smell from the mouth persists even after brushing and rinsing. This state is called chronic bad breath, halitosis or fetor oris. Bad breath can be an indication of various internal malfunctions. One should definitely consult a dentist in order to find the underlying cause of bad breath. There are also specific and targeted home remedies for bad breath if you know the underlying cause, and they will be beneficial in eradicating bad breath completely if they are followed regularly. 
Home Remedies for Bad Breath
Let us look at some of the best home remedies for bad breath:
When chewed slowly, hazelnuts can absorb bad breath.
A spoonful of lemon juice with a pinch of salt can remove garlic and onion odor in the breath. Apart from being an effective and easy remedy for bad breath, it also makes you feel fresh after a heavy or spicy meal. Research has proven that mouthwash made from essential oils including lemon essential oil can help in treating bad breath. 
Clove has very strong antiseptic properties that can kill bacteria which cause bad breath. 3-4 cloves should be ground, added to a cup of water, and boiled. This is then strained with a fine mesh and used for gargling.
Parsley, Mint & Basil
Parsley, mint, and basil leaves can be chewed because they reduce intestinal gas production and induce fresh breath for an extended period of time.
Cardamom is often taken after meals as a breath freshener. When chewed, this produces a sweet-smelling oil and improves the taste in your mouth. Cardamom contains cineole, an active component which has powerful antiseptic properties. Cineole kills the bacteria which causes bad breath. 
Fennel seeds can be taken directly or ground into powder and then used for brushing for fresh breath. The extract can also be applied to the tongue and gums.
Cinnamon can absorb the sulfurous odor of garlic and onion. A small piece of a cinnamon stick can be kept in the mouth for some time until the rotten smell is gone.
Apples, Carrots & Pears
Fruits like apples, carrots, and pears are rich in fiber. These fruits produce saliva when chewed and also aid in cleansing the teeth simply by eating them.
Mint and Wintergreen
Mint and wintergreen neutralize bad breath and bring freshness to the mouth. This is why they are present in most toothpaste and mouthwashes. The Doctors Book of Home Remedies recommends the use of mint and wintergreen mouthwash as well as a mint gum to counter the bad breath. 
Apple Cider Vinegar
A spoonful of apple cider vinegar can be taken with a glass of water before meals, resulting in improved digestion. This is because bad breath could be caused by excess acid produced by your digestive tract or by “bad” gut bacteria.
Parsley, Clove & Myrrh Tea
Tea made by boiling leaves of parsley, powdered myrrh (1 teaspoon), and whole cloves (2-4) can be brewed and stored for a few days. This should be used as a mouthwash 2-3 times a day.
Teeth can be brushed with a pinch of baking soda. This reduces the acidity in the mouth and improves the smell of your breath.
Along with these remedial procedures, proper oral hygiene must be practiced, including timely cleaning, flushing, and flossing of your mouth. Regular dental checkups should include filling cavities and getting your teeth cleaned. This will make you a confident person with a cheerful smile!