"Hi Dr Emma, I have multiple food allergies and sensitivities, which means I use pharmacy plain toothpaste. I was wondering if there is a mouthwash that would be appropriate for me to use also? I can't have artificial sweeteners (excepting stevia), and it would be preferable for me not have any added flavourings too. Thanks, Felicity. " (Plimpton SA)
The general rule with mouthwash is that most people don't need to use it regularly. If brushing and flossing is being done correctly with a fluoride toothpaste, there's not much that an everyday mouthwash will add. Mechanical removal of plaque, actually scrubbing it off, is much more effective than trying to kill the bugs with chemicals.
The exception is when there's a specific therapeutic goal in mind. Examples could include:
After oral surgery to reduce the chance of infection.
After oral surgery to improve clotting in patients at risk of bleeding.
For treatment of specific oral infections.
Fluoride mouthwash for high decay risk patients.
To help with the symptoms of medically diagnosed dry mouth.
As an adjunct to periodontal therapy, (for severe gum disease).
To relieve the symptoms of inflammatory mucosal conditions like lichen planus.
Each of these situations requires a different type of mouthwash. They all contain different active ingredients, but just happen to come in the form of a liquid you swish around your mouth. Lumping them all together is a bit like asking your doctor, "What tablets should I take?". Unless your dentist, dental specialist, or doctor has recommended a specific mouthwash for your individual needs, it's likely not necessary.
My advice for you is to speak to your dentist about your concerns. Someone with a lot of allergies would need to have a really good reason to use a mouthwash as there's a risk of having an adverse reaction to one of the ingredients. If there's no good reason for you to be using a mouthwash, the best one for you to use is none!