Is it possible for dentyl active mouthwash to stain your teeth?

Yes: Not sure what you mean by dentyl active mouthwash, but there are some prescribed or given out by your dentist mouthwashes that can stain your teeth. Mouthwashes with Chlorhexidine kill germs and make your gums healthy but do stain teeth. You will have to get it professionally cleaned to remove. Talk to the doctor.

Definitely, yes: Most of the mouthwashes have powerful antibacterial properties, and can be especially helpful in maintaining a healthy mouth. However they can cause brown stains on teeth, because some mouthwashes bind to both hard and soft tissues. The good news is that these stains are removable by a dental cleaning.