True to its name, Dual Chamber Mouthwash is housed in two separate chambers within the same bottle. One chamber contains highly diluted hydrogen peroxide. The other contains baking soda and essential oils. When the bottle is poured, these components cause an active burst of a ph-positive solution that we at GuruNanda call Oxyburst.  The synergistic effects of Oxyburst oxidize the stains and help gently remove them without sensitivity. Unlike many mouthwashes on the market, Dual Chamber Mouthwash is not harsh and contains no synthetic flavors, colors, or chemicals. The additional oxygen release may also help get rid of anaerobic bacteria. 

Instances of this are very rare. If you experience this, continue usage immediately and try a product like GuruNanda Coconut + Mint Pulling Oil that does not contain hydrogen peroxide.

Yes, but context matters here. Citric acid is a natural preservative, and what keeps the mouthwash from developing harmful bacteria on the shelf. If we did not use citric acid, we would be forced to use a synthetic preservative that kills the good oral bacteria in your mouth, as well as leading to dry mouth, sores, and even teeth staining.  Citric acid is present in much higher quantities in some foods than it is in our mouthwash. 

We always recommend that you consult your doctor about anything you put in your mouth and on your body while breastfeeding. Dual Chamber Mouthwash is not meant to be ingested, just swished and spit out. It should not have negative effects–but please consult your doctor.