Chlorhexidine has good "substantivity" (the ability of a mouthwash to bind to hard and soft tissues in the mouth). However, chlorhexidine binds to tannins, meaning that prolonged use in persons who consume coffee, tea or red wine is associated with extrinsic staining (i.e. removable staining) of teeth. Chlorhexidine mouthwash can also cause taste disturbance or alteration. Chlorhexidine is rarely associated with other issues like overgrowth of enterobacteria in persons with leukemia, desquamation and irritation of oral mucosa, salivary gland pain and swelling, and hypersensitivity reactions including anaphylaxis. A randomized clinical trial conducted in Rabat university in Morocco found better results in plaque inhibition when chlorohexidine with alcohol base 0.12% was used, when compared to an alcohol free 0.1% chlorhexidine mouthrinse. Chlorhexidine mouthrinses increase staining score of teeth over a period of time. However, many publications and, in recent times, also a systematic review (van Swaaij 2020) revealed that an AntiDiscoloration System (ADS) based on L-ascorbic acid and sodium metabisulphite is able to reduce tooth staining without affecting the antibacterial effect of chlorhexidine